Proton exchange membrane fuel cell (PEMFC) is deemed as an efficient and eco-friendly technology with high energy conversion rate and low start-up temperature. Large-scale commercialization of PEMFC, however, has been severely retarded by insufficient power, short life span and high costs of Pt-based catalysts. Substantial progress on cost-effective single-atom catalysts (SACs) have witnessed significant improvements of sluggish cathodic oxygen reduction reaction (ORR) and anodic hydrogen oxidation reaction (HOR) for PEMFC. Nevertheless, practical application of SACs is plagued by degradation issues even though numerous studies said that SACs are comparable or even surpass Pt/C catalysts. The resulting question, “What is the Achilles’ heel of SACs towards practical PEMFC application?” is herein the centerpiece of this review. Recent advanced development of SACs towards PEMFC devices, covering HOR and ORR is presented from fundamental insights to practical application. In view of the requirement for efficient PEMFC, the structure design and regulation of SACs are targeted to improve the performance and service life of PEMFC. This review points out the existing issues and design principles of SACs, which are expected to pave the way for efficient PEMFC application.
Kirubakaran, A.; Jain, S.; Nema, R. K. A review on fuel cell technologies and power electronic interface. Renewable Sustainable Energy Rev. 2009, 13, 2430–2440.
Sharma, S.; Pollet, B. G. Support materials for PEMFC and DMFC electrocatalysts-a review. J. Power Sources 2012, 208, 96–119.
Wang, Y.; Pang, Y. H.; Xu, H.; Martinez, A.; Chen, K. S. PEM fuel cell and electrolysis cell technologies and hydrogen infrastructure development-a review. Energy Environ. Sci. 2022, 15, 2288–2328.
Liu, M. L.; Zhao, Z. P.; Duan, X. F.; Huang, Y. Nanoscale structure design for high-performance Pt-based ORR catalysts. Adv. Mater. 2019, 31, 1802234.
Mohan, R.; Modak, A.; Schechter, A. Plasma-modified FeGly/C as a Pt-free stable ORR electrocatalyst in an acid electrolyte. ACS Appl. Energy Mater. 2021, 4, 564–574.
Wang, D. L.; Xin, H. L.; Hovden, R.; Wang, H. S.; Yu, Y. C.; Muller, D. A.; DiSalvo, F. J.; Abruña, H. D. Structurally ordered intermetallic platinum-cobalt core-shell nanoparticles with enhanced activity and stability as oxygen reduction electrocatalysts. Nat. Mater. 2013, 12, 81–87.
Ocampo-Restrepo, V. K.; Calderón-Cárdenas, A.; Lizcano-Valbuena, W. H. Catalytic activity of Pt-based nanoparticles with Ni and Co for ethanol and acetaldehyde electrooxidation in alkaline medium. Electrochim. Acta 2017, 246, 475–483.
Qiao, B. T.; Wang, A. Q.; Yang, X. F.; Allard, L. F.; Jiang, Z.; Cui, Y. T.; Liu, J. Y.; Li, J.; Zhang, T. Single-atom catalysis of CO oxidation using Pt1/FeO x . Nat. Chem. 2011, 3, 634–641.
Yang, X. F.; Wang, A. Q.; Qiao, B. T.; Li, J.; Liu, J. Y.; Zhang, T. Single-atom catalysts: A new frontier in heterogeneous catalysis. Acc. Chem. Res. 2013, 46, 1740–1748.
Zhou, A. W.; Wang, D. S.; Li, Y. D. Hollow microstructural regulation of single-atom catalysts for optimized electrocatalytic performance. Microstructures 2022, 2, 2022005.
Chen, Y. Q.; Yao, Y. J.; Xia, Y. J.; Mao, K.; Tang, G.; Wu, Q.; Yang, L. J.; Wang, X. Z.; Sun, X. H.; Hu, Z. Advanced Ni–N x –C single-site catalysts for CO2 electroreduction to CO based on hierarchical carbon nanocages and S-doping. Nano Res. 2020, 13, 2777–2783.
Zhang, H. G.; Hwang, S.; Wang, M. Y.; Feng, Z. X.; Karakalos, S.; Luo, L. L.; Qiao, Z.; Xie, X. H.; Wang, C. M.; Su, D. et al. Single atomic iron catalysts for oxygen reduction in acidic media: Particle size control and thermal activation. J. Am. Chem. Soc. 2017, 139, 14143–14149.
Miao, Z. P.; Wang, X. M.; Tsai, M. C.; Jin, Q. Q.; Liang, J. S.; Ma, F.; Wang, T. Y.; Zheng, S. J.; Hwang, B. J.; Huang, Y. H. et al. Atomically dispersed Fe–N x /C electrocatalyst boosts oxygen catalysis via a new metal-organic polymer supramolecule strategy. Adv. Energy Mater. 2018, 8, 1801226.
Wan, X.; Liu, X. F.; Li, Y. C.; Yu, R. H.; Zheng, L. R.; Yan, W. S.; Wang, H.; Xu, M.; Shui, J. L. Fe–N–C electrocatalyst with dense active sites and efficient mass transport for high-performance proton exchange membrane fuel cells. Nat. Catal. 2019, 2, 259–268.
Shi, Q. R.; He, Y. H.; Bai, X. W.; Wang, M. Y.; Cullen, D. A.; Lucero, M.; Zhao, X. H.; More, K. L.; Zhou, H.; Feng, Z. X. et al. Methanol tolerance of atomically dispersed single metal site catalysts: Mechanistic understanding and high-performance direct methanol fuel cells. Energy Environ. Sci. 2020, 13, 3544–3555.
Qiao, Z.; Wang, C. Y.; Li, C. Z.; Zeng, Y. C.; Hwang, S.; Li, B. Y.; Karakalos, S.; Park, J.; Kropf, A. J.; Wegener, E. C. et al. Atomically dispersed single iron sites for promoting Pt and Pt3Co fuel cell catalysts: Performance and durability improvements. Energy Environ. Sci. 2021, 14, 4948–4960.
Shi, L.; Lin, X. N.; Liu, F.; Long, Y. D.; Cheng, R. Y.; Tan, C. H.; Yang, L.; Hu, C. G.; Zhao, S. L.; Liu, D. Geometrically deformed iron-based single-atom catalysts for high-performance acidic proton exchange membrane fuel cells. ACS Catal. 2022, 12, 5397–5406.
Bae, G.; Kim, M. M.; Han, M. H.; Cho, J.; Kim, D. H.; Sougrati, M. T.; Kim, J.; Lee, K. S.; Joo, S. H.; Goddard, W. A. et al. Unravelling the complex causality behind Fe–N–C degradation in fuel cells. Nat. Catal. 2023, 6, 1140–1150.
Wang, X. X.; Cullen, D. A.; Pan, Y. T.; Hwang, S.; Wang, M. Y.; Feng, Z. X.; Wang, J. Y.; Engelhard, M. H.; Zhang, H. G.; He, Y. H.et al. Nitrogen-coordinated single cobalt atom catalysts for oxygen reduction in proton exchange membrane fuel cells. Adv. Mater. 2018, 30, 1706758.
Zhang, N.; Zhou, T. P.; Chen, M. L.; Feng, H.; Yuan, R. L.; Zhong, C. A.; Yan, W. S.; Tian, Y. C.; Wu, X. J.; Chu, W. S. et al. High-purity pyrrole-type FeN4 sites as a superior oxygen reduction electrocatalyst. Energy Environ. Sci. 2020, 13, 111–118.
Wang, H. W.; Gao, J. L.; Chen, C. L.; Zhao, W.; Zhang, Z. H.; Li, D.; Chen, Y.; Wang, C. Y.; Zhu, C.; Ke, X. X. et al. PtNi–W/C with atomically dispersed tungsten sites toward boosted ORR in proton exchange membrane fuel cell devices. Nano-Micro Lett. 2023, 15, 143.
Debe, M. K. Electrocatalyst approaches and challenges for automotive fuel cells. Nature 2012, 486, 43–51.
Xu, Z. T.; Qiu, D. K.; Yi, P. Y.; Peng, L. F.; Lai, X. M. Towards mass applications: A review on the challenges and developments in metallic bipolar plates for PEMFC. Prog. Nat. Sci.: Mater. Int. 2020, 30, 815–824.
Li, H. D.; Zhao, H.; Jian, S.; Tao, B. R.; Gu, S. N.; Xu, G. X.; Wang, G. F.; Chang, H. X. Designing proton exchange membrane fuel cells with high specific power density. J. Mater. Chem. A 2023, 11, 17373–17391.
Wang, Y.; Ruiz Diaz, D. F.; Chen, K. S.; Wang, Z.; Adroher, X. C. Materials, technological status, and fundamentals of PEM fuel cells-a review. Mater. Today 2020, 32, 178–203.
Xing, L.; Shi, W. D.; Su, H. N.; Xu, Q.; Das, P. K.; Mao, B. D.; Scott, K. Membrane electrode assemblies for PEM fuel cells: A review of functional graded design and optimization. Energy 2019, 177, 445–464.
Galizzioli, D.; Trasatti, S. Work function, electronegativity, and electrochemical behaviour of metals: IV. Simple electron exchange reactions. Fe2+/Fe3+ redox couple. J. Electroanal. Chem. Interfacial Electrochem. 1973, 44, 367–388.
Markovic, N. M.; Ross, P. N. New electrocatalysts for fuel cells from model surfaces to commercial catalysts. CATTECH 2000, 4, 110–126.
Steele, B. C. H.; Heinzel, A. Materials for fuel-cell technologies. Nature 2001, 414, 345–352.
Pedersen, C. M.; Escudero-Escribano, M.; Velázquez-Palenzuela, A.; Christensen, L. H.; Chorkendorff, I.; Stephens, I. E. L. Benchmarking Pt-based electrocatalysts for low temperature fuel cell reactions with the rotating disk electrode: Oxygen reduction and hydrogen oxidation in the presence of CO (review article). Electrochim. Acta 2015, 179, 647–657.
Nie, Y.; Li, L.; Wei, Z. D. Recent advancements in Pt and Pt-free catalysts for oxygen reduction reaction. Chem. Soc. Rev. 2015, 44, 2168–2201.
Alarawi, A.; Ramalingam, V.; He, J. H. Recent advances in emerging single atom confined two-dimensional materials for water splitting applications. Mater. Today Energy 2019, 11, 1–23.
Zhang, L. L.; Wang, A. Q.; Miller, J. T.; Liu, X. Y.; Yang, X. F.; Wang, W. T.; Li, L.; Huang, Y. Q.; Mou, C. Y.; Zhang, T. Efficient and durable Au alloyed Pd single-atom catalyst for the ullmann reaction of aryl chlorides in water. ACS Catal. 2014, 4, 1546–1553.
Hardisty, S. S.; Lin, X. Q.; Kucernak, A. R. J.; Zitoun, D. Single-atom Pt on carbon nanotubes for selective electrocatalysis. Carbon Energy 2024, 6, e409.
Zhou, Y. J.; Yu, F. Y.; Lang, Z. L.; Nie, H. D.; Wang, Z. Z.; Shao, M. W.; Liu, Y.; Tan, H. Q.; Li, Y. G.; Kang, Z. H. Carbon dots/PtW6O24 composite as efficient and stable electrocatalyst for hydrogen oxidation reaction in PEMFCs. Chem. Eng. J. 2021, 426, 130709.
Yang, Z. J.; Chen, C. Q.; Zhao, Y. X.; Wang, Q.; Zhao, J. Q.; Waterhouse, G. I. N.; Qin, Y.; Shang, L.; Zhang, T. R. Pt single atoms on CrN nanoparticles deliver outstanding activity and CO tolerance in the hydrogen oxidation reaction. Adv. Mater. 2023, 35, 2208799.
Li, H.; Wang, X.; Gong, X.; Liu, C.; Ge, J. J.; Song, P.; Xu, W. L. “One stone three birds” of a synergetic effect between Pt single atoms and clusters makes an ideal anode catalyst for fuel cells. J. Mater. Chem. A 2023, 11, 14826–14832.
Yin, L. L.; Zhang, S.; Sun, M. Z.; Wang, S. Y.; Huang, B. L.; Du, Y. P. Heteroatom-driven coordination fields altering single cerium atom sites for efficient oxygen reduction reaction. Adv. Mater. 2023, 35, 2302485.
Liu, F.; Meng, J. S.; Jiang, G. P.; Li, J. T.; Wang, H.; Xiao, Z. T.; Yu, R. H.; Mai, L.; Wu, J. S. Coordination engineering of metal single atom on carbon for enhanced and robust potassium storage. Matter 2021, 4, 4006–4021.
Lin, L.; Ni, Y. X.; Shang, L.; Sun, H. X.; Zhang, Q.; Zhang, W.; Yan, Z. H.; Zhao, Q.; Chen, J. Atomic-level modulation-induced electron redistribution in Co coordination polymers elucidates the oxygen reduction mechanism. ACS Catal. 2022, 12, 7531–7540.
Han, Y. H.; Wang, Y. G.; Xu, R. R.; Chen, W. X.; Zheng, L. R.; Han, A. J.; Zhu, Y. Q.; Zhang, J.; Zhang, H. B.; Luo, J. et al. Electronic structure engineering to boost oxygen reduction activity by controlling the coordination of the central metal. Energy Environ. Sci. 2018, 11, 2348–2352.
Sun, Y. Q.; Li, X. L.; Zhang, T.; Xu, K.; Yang, Y. S.; Chen, G. Z.; Li, C. C.; Xie, Y. Nitrogen-doped cobalt diselenide with cubic phase maintained for enhanced alkaline hydrogen evolution. Angew. Chem., Int. Ed. 2021, 60, 21575–21582 .
Jin, S.; Hao, Z. M.; Zhang, K.; Yan, Z. H.; Chen, J. Advances and challenges for the electrochemical reduction of CO2 to CO: From fundamentals to industrialization. Angew. Chem., Int. Ed. 2021, 60, 20627–20648.
Liang, X.; Fu, N. H.; Yao, S. C.; Li, Z.; Li, Y D. The progress and outlook of metal single-atom-site catalysis. J. Am. Chem. Soc. 2022, 144, 18155–18174.
Li, W. X.; Guo, Z. H.; Yang, J.; Li, Y.; Sun, X. L.; He, H. Y.; Li, S. A.; Zhang, J. J. Advanced strategies for stabilizing single-atom catalysts for energy storage and conversion. Electrochem. Energy Rev. 2022, 5, 9.
Shi, G. D.; Xie, Y. L.; Du, L. L.; Fu, X. L.; Chen, X. J.; Xie, W. J.; Lu, T. B.; Yuan, M. J.; Wang, M. Constructing Cu–C bonds in a graphdiyne-regulated Cu single-atom electrocatalyst for CO2 reduction to CH4. Angew. Chem., Int. Ed. 2022, 61, e202203569.
Wang, Q.; Su, J. C.; Chen, H. L.; Wang, D. Q.; Tian, X. Y.; Zhang, Y. J.; Feng, X.; Wang, S.; Li, J.; Jin, H. L. Highly conductive nitrogen-doped sp2/sp3 hybrid carbon as a conductor-free charge storage host. Adv. Funct. Mater. 2022, 32, 2209201.
Cheng, J. R.; Lyu, C. J.; Li, H. R.; Wu, J. W.; Hu, Y.; Han, B.; Wu, K. L.; Hojamberdiev, M.; Geng, D. S. Steering the oxygen reduction reaction pathways of N-carbon hollow spheres by heteroatom doping. Appl. Catal.: B Environ. 2023, 327, 122470.
Chen, X. H.; Ye, P. C.; Wang, H. Y.; Huang, H.; Zhong, Y. J.; Hu, Y. Discriminating active B–N sites in coralloidal B, N dual-doped carbon nano-bundles for boosted Zn-ion storage capability. Adv. Funct. Mater. 2023, 33, 2212915.
Zhang, Z.; Jiang, C.; Li, P.; Feng, Q.; Zhao, Z. L.; Yao, K. G.; Fan, J. T.; Li, H.; Wang, H. J. Pt atoms on doped carbon nanosheets with ultrahigh N content as a superior bifunctional catalyst for hydrogen evolution/oxidation. Sustainable Energy Fuels 2021, 5, 532–539.
Bampos, G.; Tsatsos, S.; Kyriakou, G.; Bebelis, S. Pd-based bimetallic electrocatalysts for hydrogen oxidation reaction in acidic medium. J. Electroanal. Chem. 2023, 928, 117008.
Weber, D. J.; Dosche, C.; Oezaslan, M. Tuning of Pt–Co nanoparticle motifs for enhancing the HOR performance in alkaline media. J. Mater. Chem. A 2021, 9, 15415–15431.
Ghosh, A.; Chandran, P.; Ramaprabhu, S. Palladium-nitrogen coordinated cobalt alloy towards hydrogen oxidation and oxygen reduction reactions with high catalytic activity in renewable energy generations of proton exchange membrane fuel cell. Appl. Energy 2017, 208, 37–48.
Chen, G. Z.; Chen, W.; Lu, R. H.; Ma, C.; Zhang, Z. D.; Huang, Z. Y.; Weng, J. N.; Wang, Z. Y.; Han, Y. H.; Huang, W. Near-atomic-scale superfine alloy clusters for ultrastable acidic hydrogen electrocatalysis. J. Am. Chem. Soc. 2023, 145, 22069–22078.
Zeng, H. B.; Chen, S. Q.; Jin, Y. Q.; Li, J. W.; Song, J. D.; Le, Z. C.; Liang, G. F.; Zhang, H.; Xie, F. Y.; Chen, J. et al. Electron density modulation of metallic MoO2 by Ni doping to produce excellent hydrogen evolution and oxidation activities in acid. ACS Energy Lett. 2020, 5, 1908–1915.
Yu, X.; Tian, H.; Fu, Z. Q.; Pei, F. L.; Peng, L. X.; Meng, G.; Kong, F. T.; Chen, Y. F.; Chen, C.; Chang, Z. W. et al. Strengthening the hydrogen spillover effect via the phase transformation of W18O49 for boosted hydrogen oxidation reaction. ACS Catal. 2023, 13, 2834–2846.
Zhang, P.; Chen, K.; Li, J. Y.; Wang, M. M.; Li, M.; Liu, Y. Q.; Pan, Y. Bifunctional Single atom catalysts for rechargeable zinc-air batteries: From dynamic mechanism to rational design. Adv. Mater. 2023, 35, 2303243.
Zhao, J. J.; Fu, C. H.; Ye, K.; Liang, Z.; Jiang, F. L.; Shen, S. Y.; Zhao, X. R.; Ma, L.; Shadike, Z.; Wang, X. M. et al. Manipulating the oxygen reduction reaction pathway on Pt-coordinated motifs. Nat. Commun. 2022, 13, 685.
Ni, B. X.; Shen, P.; Zhang, G. R.; Zhao, J. J.; Ding, H. H.; Ye, Y. F.; Yue, Z. Y.; Yang, H.; Wei, H.; Jiang, K. Second-shell N dopants regulate acidic O2 reduction pathways on isolated Pt sites. J. Am. Chem. Soc. 2024, 146, 11181–11192.
Li, T. F.; Liu, J. J.; Song, Y.; Wang, F. Photochemical solid-phase synthesis of platinum single atoms on nitrogen-doped carbon with high loading as bifunctional catalysts for hydrogen evolution and oxygen reduction reactions. ACS Catal. 2018, 8, 8450–8458.
Yang, S.; Kim, J.; Tak, Y. J.; Soon, A.; Lee, H. Single-atom catalyst of platinum supported on titanium nitride for selective electrochemical reactions. Angew. Chem., Int. Ed. 2016, 55, 2058–2062.
Choi, C. H.; Kim, M.; Kwon, H. C.; Cho, S. J.; Yun, S.; Kim, H. T.; Mayrhofer, K. J. J.; Kim, H.; Choi, M. Tuning selectivity of electrochemical reactions by atomically dispersed platinum catalyst. Nat. Commun. 2016, 7, 10922.
Liu, J.; Jiao, M. G.; Lu, L. L.; Barkholtz, H. M.; Li, Y. P.; Wang, Y.; Jiang, L. H.; Wu, Z. J.; Liu, D. J.; Zhuang, L. et al. High performance platinum single atom electrocatalyst for oxygen reduction reaction. Nat. Commun. 2017, 8, 15938.
Liu, J.; Jiao, M. G.; Mei, B. B.; Tong, Y. X.; Li, Y. P.; Ruan, M. B.; Song, P.; Sun, G. Q.; Jiang, L. H.; Wang, Y. et al. Carbon-supported divacancy-anchored platinum single-atom electrocatalysts with superhigh Pt utilization for the oxygen reduction reaction. Angew. Chem., Int. Ed. 2019, 58, 1163–1167.
Ou, Z. Q.; An, Z.; Ma, Z.; Li, N.; Han, Y. N.; Yang, G. J.; Jiang, Q. K.; Chen, Q.; Chu, W. L.; Wang, S. L. et al. 3D porous graphene-like carbons encaged single-atom-based Pt for ultralow loading and high-performance fuel cells. ACS Catal. 2023, 13, 1856–1862.
Cheng, X.; Wang, Y. S.; Lu, Y.; Zheng, L. R.; Sun, S. R.; Li, H. Y.; Chen, G.; Zhang, J. J. Single-atom alloy with Pt–Co dual sites as an efficient electrocatalyst for oxygen reduction reaction. Appl. Catal.: B Environ. 2022, 306, 121112.
Xiao, M. L.; Zhu, J. B.; Li, G. R.; Li, N.; Li, S.; Cano, Z. P.; Ma, L.; Cui, P. X.; Xu, P.; Jiang, G. P. et al. A single-atom iridium heterogeneous catalyst in oxygen reduction reaction. Angew. Chem., Int. Ed. 2019, 58, 9640–9645.
Liu, Q. T.; Li, Y. C.; Zheng, L. R.; Shang, J. X.; Liu, X. F.; Yu, R. H.; Shui, J. L. Sequential synthesis and active-site coordination principle of precious metal single-atom catalysts for oxygen reduction reaction and PEM fuel cells. Adv. Energy Mater. 2020, 10, 2000689.
Peera, S. G.; Sahu, A. K.; Bhat, S. D.; Lee, S. C. Nitrogen functionalized graphite nanofibers/Ir nanoparticles for enhanced oxygen reduction reaction in polymer electrolyte fuel cells (PEFCs). RSC Adv. 2014, 4, 11080–11088.
Strickler, A. L.; Jackson, A.; Jaramillo, T. F. Active and stable Ir@Pt core-shell catalysts for electrochemical oxygen reduction. ACS Energy Lett. 2016, 2, 244–249.
Peng, X. Y.; Zhao, S. Z.; Mi, Y. Y.; Han, L. L.; Liu, X. J.; Qi, D. F.; Sun, J. Q.; Liu, Y. F.; Bao, H. H.; Zhuo, L. C. et al. Trifunctional single-atomic Ru sites enable efficient overall water splitting and oxygen reduction in acidic media. Small 2020, 16, 2002888.
Zhang, C. H.; Sha, J. W.; Fei, H. L.; Liu, M. J.; Yazdi, S.; Zhang, J. B.; Zhong, Q. F.; Zou, X. L.; Zhao, N. Q.; Yu, H. S. et al. Single-atomic ruthenium catalytic sites on nitrogen-doped graphene for oxygen reduction reaction in acidic medium. ACS Nano 2017, 11, 6930–6941.
Chung, D. Y.; Yoo, J. M.; Sung, Y. E. Highly durable and active Pt-based nanoscale design for fuel-cell oxygen-reduction electrocatalysts. Adv. Mater. 2018, 30, 1704123.
Shao, M. H.; Chang, Q. W.; Dodelet, J. P.; Chenitz, R. Recent advances in electrocatalysts for oxygen reduction reaction. Chem. Rev. 2016, 116, 3594–3657.
Jasinski, R. A new fuel cell cathode catalyst. Nature 1964, 201, 1212–1213.
Wang, X. Q.; Li, Z. J.; Qu, Y. T.; Yuan, T. W.; Wang, W. Y.; Wu, Y. E.; Li, Y. D. Review of metal catalysts for oxygen reduction reaction: From nanoscale engineering to atomic design. Chem 2019, 5, 1486–1511.
He, Y. H.; Tan, Q.; Lu, L. L.; Sokolowski, J.; Wu, G. Metal-nitrogen-carbon catalysts for oxygen reduction in PEM fuel cells: Self-template synthesis approach to enhancing catalytic activity and stability. Electrochem. Energy Rev. 2019, 2, 231–251.
Zhang, G. X.; Jia, Y.; Zhang, C.; Xiong, X. Y.; Sun, K.; Chen, R. D.; Chen, W. X.; Kuang, Y.; Zheng, L. R.; Tang, H. L. et al. A general route via formamide condensation to prepare atomically dispersed metal-nitrogen-carbon electrocatalysts for energy technologies. Energy Environ. Sci. 2019, 12, 1317–1325.
Lin, Y. C.; Liu, P. Y.; Velasco, E.; Yao, G.; Tian, Z. Q.; Zhang, L. J.; Chen, L. Fabricating single-atom catalysts from chelating metal in open frameworks. Adv. Mater. 2019, 31, 1808193.
Mun, Y.; Lee, S.; Kim, K.; Kim, S.; Lee, S.; Han, J. W.; Lee, J. Versatile strategy for tuning ORR activity of a single Fe–N4 site by controlling electron-withdrawing/donating properties of a carbon plane. J. Am. Chem. Soc. 2019, 141, 6254–6262.
Tian, N.; Lu, B. A.; Yang, X. D.; Huang, R.; Jiang, Y. X.; Zhou, Z. Y.; Sun, S. G. Rational design and synthesis of low-temperature fuel cell electrocatalysts. Electrochem. Energy Rev. 2018, 1, 54–83.
Hu, C. G.; Xiao, Y.; Zou, Y. Q.; Dai, L. M. Carbon-based metal-free electrocatalysis for energy conversion, energy storage, and environmental protection. Electrochem. Energy Rev. 2018, 1, 84–112.
Lu, Z. S.; Xu, G. L.; He, C. Z.; Wang, T. X.; Yang, L.; Yang, Z. X.; Ma, D. W. Novel catalytic activity for oxygen reduction reaction on MnN4 embedded graphene: A dispersion-corrected density functional theory study. Carbon 2015, 84, 500–508.
Kattel, S.; Wang, G. F. Reaction pathway for oxygen reduction on FeN4 embedded graphene. J. Phys. Chem. Lett. 2014, 5, 452–456.
Deng, C. F.; He, R. X.; Shen, W.; Li, M.; Zhang, T. A single-atom catalyst of cobalt supported on a defective two-dimensional boron nitride material as a promising electrocatalyst for the oxygen reduction reaction: A DFT study. Phys. Chem. Chem. Phys. 2019, 21, 6900–6907.
Wu, Y.; Li, C.; Liu, W.; Li, H. H.; Gong, Y. Y.; Niu, L. Y.; Liu, X. J.; Sun, C. Q.; Xu, S. Q. Unexpected monoatomic catalytic-host synergetic OER/ORR by graphitic carbon nitride: Density functional theory. Nanoscale 2019, 11, 5064–5071.
Zhu, C. Z.; Fu, S. F.; Shi, Q. R.; Du, D.; Lin, Y. H. Single-atom electrocatalysts. Angew. Chem., Int. Ed. 2017, 56, 13944–13960.
Deng, D. H.; Chen, X. Q.; Yu, L.; Wu, X.; Liu, Q. F.; Liu, Y.; Yang, H. X.; Tian, H. F.; Hu, Y. F.; Du, P. P. et al. A single iron site confined in a graphene matrix for the catalytic oxidation of benzene at room temperature. Sci. Adv. 2015, 1, e1500462.
Zhang, H. B.; Wei, J.; Dong, J. C.; Liu, G. G.; Shi, L.; An, P. F.; Zhao, G. X.; Kong, J. T.; Wang, X. J.; Meng, X. G. et al. Efficient visible-light-driven carbon dioxide reduction by a single-atom implanted metal-organic framework. Angew. Chem., Int. Ed. 2016, 55, 14310–14314.
Gawande, M. B.; Fornasiero, P.; Zbořil, R. Carbon-based single-tom catalysts for advanced applications. ACS Catal. 2020, 10, 2231–2259.
Chen, M. J.; He, Y. H.; Spendelow, J. S.; Wu, G. Atomically dispersed metal catalysts for oxygen reduction. ACS Energy Lett. 2019, 4, 1619–1633.
Wang, Y. Q.; Hao, J. Y.; Liu, Y.; Liu, M.; Sheng, K.; Wang, Y.; Yang, J.; Li, J.; Li, W. Z. Recent advances in regulating the performance of acid oxygen reduction reaction on carbon-supported non-precious metal single atom catalysts. J. Energy Chem. 2023, 76, 601–616.
Deng, Y. J.; Luo, J. M.; Chi, B.; Tang, H. B.; Li, J.; Qiao, X. C.; Shen, Y. J.; Yang, Y. J.; Jia, C. M.; Rao, P. et al. Advanced atomically dispersed metal-nitrogen-carbon catalysts toward cathodic oxygen reduction in PEM fuel cells. Adv. Energy Mater. 2021, 11, 2101222.
Asset, T.; Atanassov, P. Iron-nitrogen-carbon catalysts for proton exchange membrane fuel cells. Joule 2020, 4, 33–44.
Zhang, H. G.; Chung, H. T.; Cullen, D. A.; Wagner, S.; Kramm, U. I.; More, K. L.; Zelenay, P.; Wu, G. High-performance fuel cell cathodes exclusively containing atomically dispersed iron active sites. Energy Environ. Sci. 2019, 12, 2548–2558.
Miao, Z. P.; Wang, X. M.; Zhao, Z. L.; Zuo, W. B.; Chen, S. Q.; Li, Z. Q.; He, Y. H.; Liang, J. S.; Ma, F.; Wang, H. L. et al. Improving the stability of non-noble-metal M–N–C catalysts for proton-exchange-membrane fuel cells through M–N bond length and coordination regulation. Adv. Mater. 2021, 33, 2006613.
Shi, X. D.; Pu, Z. H.; Chi, B.; Liu, M. R.; Yu, S. Y.; Zheng, L.; Yang, L. J.; Shu, T.; Liao, S. J. Nitrogen and atomic Fe dual-doped porous carbon nanocubes as superior electrocatalysts for acidic H2–O2 PEMFC and alkaline Zn-air battery. J. Energy Chem. 2021, 59, 388–395.
Zhou, Y. Z.; Chen, G. B.; Wang, Q.; Wang, D.; Tao, X. F.; Zhang, T. R.; Feng, X. L.; Müllen, K. Fe–N–C electrocatalysts with densely accessible Fe–N4 sites for efficient oxygen reduction reaction. Adv. Funct. Mater. 2021, 31, 2102420.
Yuan, L. J.; Liu, B.; Shen, L. X.; Dai, Y. K.; Li, Q.; Liu, C.; Gong, W.; Sui, X. L.; Wang, Z. B. d-Orbital electron delocalization realized by axial Fe4C atomic clusters delivers high-performance Fe–N–C catalysts for oxygen reduction reaction. Adv. Mater. 2023, 35, 2305945.
Yang, L.; Cheng, D. J.; Xu, H. X.; Zeng, X. F.; Wan, X.; Shui, J. L.; Xiang, Z. H.; Cao, D. P. Unveiling the high-activity origin of single-atom iron catalysts for oxygen reduction reaction. Proc. Natl. Acad. Sci. USA 2018, 115, 6626–6631.
Xie, X. Y.; Shang, L.; Xiong, X. Y.; Shi, R.; Zhang, T. R. Fe Single-atom catalysts on MOF-5 derived carbon for efficient oxygen reduction reaction in proton exchange membrane fuel cells. Adv. Energy Mater. 2022, 12, 2102688.
Liu, F.; Shi, L.; Lin, X. N.; Yu, D. L.; Zhang, C.; Xu, R.; Liu, D.; Qiu, J. S.; Dai, L. M. Site-density engineering of single-atomic iron catalysts for high-performance proton exchange membrane fuel cells. Appl. Catal.: B Environ. 2022, 302, 120860.
Pan, Y.; Ma, X. L.; Wang, M. M.; Yang, X.; Liu, S. J.; Chen, H. C.; Zhuang, Z. W.; Zhang, Y. H.; Cheong, W. C.; Zhang, C. et al. Construction of N, P co-doped carbon frames anchored with Fe single atoms and Fe2P nanoparticles as a robust coupling catalyst for electrocatalytic oxygen reduction. Adv. Mater. 2022, 34, 2203621.
Zhao, Y. L.; Chen, H. C.; Ma, X. L.; Li, J. Y.; Yuan, Q.; Zhang, P.; Wang, M. M.; Li, J. X.; Li, M.; Wang, S. F. et al. Vacancy defects inductive effect of asymmetrically coordinated single-atom Fe–N3S1 active sites for robust electrocatalytic oxygen reduction with high turnover frequency and mass activity. Adv. Mater. 2024, 36, 2308243.
Zhang, P.; Chen, H. C.; Zhu, H. Y.; Chen, K.; Li, T. Y.; Zhao, Y. L.; Li, J. Y.; Hu, R. B.; Huang, S. Y.; Zhu, W. et al. Inter-site structural heterogeneity induction of single atom Fe catalysts for robust oxygen reduction. Nat. Commun. 2024, 15, 2062.
Gao, J. J.; Yang, H. B.; Huang, X.; Hung, S. F.; Cai, W. Z.; Jia, C. M.; Miao, S.; Chen, H. M.; Yang, X. F.; Huang, Y. Q. et al. Enabling direct H2O2 production in acidic media through rational design of transition metal single atom catalyst. Chem 2020, 6, 658–674.
Sun, Y. Y.; Silvioli, L.; Sahraie, N. R.; Ju, W.; Li, J. K.; Zitolo, A.; Li, S.; Bagger, A.; Arnarson, L.; Wang, X. L. et al. Activity-selectivity trends in the electrochemical production of hydrogen peroxide over single-site metal-nitrogen-carbon catalysts. J. Am. Chem. Soc. 2019, 141, 12372–12381.
Cheng, X. Y.; Yang, J.; Yan, W.; Han, Y.; Qu, X. M.; Yin, S. H.; Chen, C.; Ji, R. Y.; Li, Y. R.; Li, G. et al. Nano-geometric deformation and synergistic Co nanoparticles-Co–N4 composite sites for proton exchange membrane fuel cells. Energy Environ. Sci. 2021, 14, 5958–5967.
He, Y. H.; Hwang, S.; Cullen, D. A.; Uddin, M. A.; Langhorst, L.; Li, B. Y.; Karakalos, S.; Kropf, A. J.; Wegener, E. C.; Sokolowski, J. et al. Highly active atomically dispersed CoN4 fuel cell cathode catalysts derived from surfactant-assisted MOFs: Carbon-shell confinement strategy. Energy Environ. Sci. 2019, 12, 250–260.
Li, F.; Han, G. F.; Noh, H. J.; Kim, S. J.; Lu, Y. L.; Jeong, H. Y.; Fu, Z. P.; Baek, J. B. Boosting oxygen reduction catalysis with abundant copper single atom active sites. Energy Environ. Sci. 2018, 11, 2263–2269.
Qu, Y. T.; Li, Z. J.; Chen, W. X.; Lin, Y.; Yuan, T. W.; Yang, Z. K.; Zhao, C. M.; Wang, J.; Zhao, C.; Wang, X. et al. Direct transformation of bulk copper into copper single sites via emitting and trapping of atoms. Nat. Catal. 2018, 1, 781–786.
Yang, Z. H.; Jiang, K. Y.; Tong, G. S.; Ke, C. C.; Wu, H. F.; Liu, P.; Zhang, J. C.; Ji, H. P.; Zhu, J. H.; Lu, C. B. et al. Copper-involved highly efficient oxygen reduction reaction in both alkaline and acidic media. Chem. Eng. J. 2022, 437, 135377.
Peng, Q.; Zhou, J.; Chen, J. T.; Zhang, T.; Sun, Z. M. Cu single atoms on Ti2CO2 as a highly efficient oxygen reduction catalyst in a proton exchange membrane fuel cell. J. Mater. Chem. A 2019, 7, 26062–26070.
Chen, M. J.; Li, X.; Yang, F.; Li, B. Y.; Stracensky, T.; Karakalos, S.; Mukerjee, S.; Jia, Q. Y.; Su, D.; Wang, G. F. et al. Atomically dispersed MnN4 catalysts via environmentally benign aqueous synthesis for oxygen reduction: Mechanistic understanding of activity and stability improvements. ACS Catal. 2020, 10, 10523–10534.
Li, J. Z.; Chen, M. J.; Cullen, D. A.; Hwang, S.; Wang, M. Y.; Li, B. Y.; Liu, K. X.; Karakalos, S.; Lucero, M.; Zhang, H. G. et al. Atomically dispersed manganese catalysts for oxygen reduction in proton-exchange membrane fuel cells. Nat. Catal. 2018, 1, 935–945.
Wang, X. X.; Prabhakaran, V.; He, Y. H.; Shao, Y. Y.; Wu, G. Iron-free cathode catalysts for proton-exchange-membrane fuel cells: Cobalt catalysts and the peroxide mitigation approach. Adv. Mater. 2019, 31, 1805126.
Beniya, A.; Higashi, S. Towards dense single-atom catalysts for future automotive applications. Nat. Catal. 2019, 2, 590–602.
Yamazaki, S. I.; Ioroi, T.; Yamada, Y.; Yasuda, K.; Kobayashi, T. A direct CO polymer electrolyte membrane fuel cell. Angew. Chem., Int. Ed. 2006, 45, 3120–3122.
Badwal, S. P. S.; Giddey, S.; Kulkarni, A.; Goel, J.; Basu, S. Direct ethanol fuel cells for transport and stationary applications-A comprehensive review. Appl. Energy 2015, 145, 80–103.
Liu, Z. F.; Jackson, G. S.; Eichhorn, B. W. PtSn intermetallic, core-shell, and alloy nanoparticles as CO-tolerant electrocatalysts for H2 oxidation. Angew. Chem., Int. Ed. 2010, 49, 3173–3176.
Rees, N. V.; Compton, R. G. Sustainable energy: A review of formic acid electrochemical fuel cells. J. Solid State Electrochem. 2011, 15, 2095–2100.
Yang, X. L.; Wang, Y.; Wang, X.; Mei, B. B.; Luo, E. G.; Li, Y.; Meng, Q. L.; Jin, Z.; Jiang, Z.; Liu, C. P. et al. CO-tolerant PEMFC anodes enabled by synergistic catalysis between iridium single-atom sites and nanoparticles. Angew. Chem., Int. Ed. 2021, 60, 26177–26183.
Wang, X.; Yang, X. L.; Wang, Y.; Mei, B. B.; Jin, Z.; Li, Y.; Shi, Z. P.; Jiang, Z.; Liu, C. P.; Xing, W. et al. Single atom sites as CO scavenger to allow for crude hydrogen usage in PEMFC. Sci. Bull. 2024, 69, 1061–1070.
Pang, B. B.; Jia, C. Y.; Wang, S. C.; Liu, T.; Ding, T.; Liu, X. K.; Liu, D.; Cao, L. L.; Zhu, M. Z.; Liang, C. H. et al. Self-optimized ligand effect of single-atom modifier in ternary Pt-based alloy for efficient hydrogen oxidation. Nano Lett. 2023, 23, 3826–3834.
Zhang, H. G.; Osgood, H.; Xie, X. H.; Shao, Y. Y.; Wu, G. Engineering nanostructures of PGM-free oxygen-reduction catalysts using metal-organic frameworks. Nano Energy 2017, 31, 331–350.
Sahraie, N. R.; Kramm, U. I.; Steinberg, J.; Zhang, Y. J.; Thomas, A.; Reier, T.; Paraknowitsch, J. P.; Strasser, P. Quantifying the density and utilization of active sites in non-precious metal oxygen electroreduction catalysts. Nat. Commun. 2015, 6, 8618.
Xue, L. F.; Li, Y. C.; Liu, X. F.; Liu, Q. T.; Shang, J. X.; Duan, H. P.; Dai, L. M.; Shui, J. L. Zigzag carbon as efficient and stable oxygen reduction electrocatalyst for proton exchange membrane fuel cells. Nat. Commun. 2018, 9, 3819.
Banham, D.; Kishimoto, T.; Zhou, Y.; Sato, T.; Bai, K.; Ozaki, J. I.; Imashiro, Y.; Ye, S. Y. Critical advancements in achieving high power and stable nonprecious metal catalyst-based MEAs for real-world proton exchange membrane fuel cell applications. Sci. Adv. 2018, 4, eaar7180.
Choi, C. H.; Baldizzone, C.; Grote, J. P.; Schuppert, A. K.; Jaouen, F.; Mayrhofer, K. J. Stability of Fe–N–C catalysts in acidic medium studied by operando spectroscopy. Angew. Chem., Int. Ed. 2015, 54, 12753–12757.
Strickland, K.; Miner, E.; Jia, Q. Y.; Tylus, U.; Ramaswamy, N.; Liang, W. T.; Sougrati, M. T.; Jaouen, F.; Mukerjee, S. Highly active oxygen reduction non-platinum group metal electrocatalyst without direct metal-nitrogen coordination. Nat. Commun. 2015, 6, 7343.
Hu, Y.; Jensen, J. O.; Zhang, W.; Cleemann, L. N.; Xing, W.; Bjerrum, N. J.; Li, Q. F. Hollow spheres of iron carbide nanoparticles encased in graphitic layers as oxygen reduction catalysts. Angew. Chem., Int. Ed. 2014, 53, 3675–3679.
Choi, C. H.; Baldizzone, C.; Polymeros, G.; Pizzutilo, E.; Kasian, O.; Schuppert, A. K.; Ranjbar Sahraie, N.; Sougrati, M. T.; Mayrhofer, K. J. J.; Jaouen, F. Minimizing operando demetallation of Fe–N–C electrocatalysts in acidic medium. ACS Catal. 2016, 6, 3136–3146.
Kienitz, B.; Pivovar, B.; Zawodzinski, T.; Garzon, F. H. Cationic contamination effects on polymer electrolyte membrane fuel cell performance. J. Electrochem. Soc. 2011, 158, B1175.
Chenitz, R.; Kramm, U. I.; Lefèvre, M.; Glibin, V.; Zhang, G. X.; Sun, S. H.; Dodelet, J. P. A specific demetalation of Fe–N4 catalytic sites in the micropores of NC_Ar + NH3 is at the origin of the initial activity loss of the highly active Fe/N/C catalyst used for the reduction of oxygen in PEM fuel cells. Energy Environ. Sci. 2018, 11, 365–382.
Lefèvre, M.; Dodelet, J. P. Fe-based catalysts for the reduction of oxygen in polymer electrolyte membrane fuel cell conditions: Determination of the amount of peroxide released during electroreduction and its influence on the stability of the catalysts. Electrochim. Acta 2003, 48, 2749–2760.
Schulenburg, H.; Stankov, S.; Schünemann, V.; Radnik, J.; Dorbandt, I.; Fiechter, S.; Bogdanoff, P.; Tributsch, H. Catalysts for the oxygen reduction from heat-treated iron(III) tetramethoxyphenylporphyrin chloride: Structure and stability of active sites. J. Phys. Chem. B 2003, 107, 9034–9041.
Li, J. K.; Sougrati, M. T.; Zitolo, A.; Ablett, J. M.; Oğuz, I. C.; Mineva, T.; Matanovic, I.; Atanassov, P.; Huang, Y.; Zenyuk, I. et al. Identification of durable and non-durable FeN x sites in Fe–N–C materials for proton exchange membrane fuel cells. Nat. Catal. 2021, 4, 10–19.
Shi, Q. R.; Zhu, C. Z.; Du, D.; Lin, Y. H. Robust noble metal-based electrocatalysts for oxygen evolution reaction. Chem. Soc. Rev. 2019, 48, 3181–3192.
Wang, Y. N.; Wan, X.; Liu, J. Y.; Li, W. W.; Li, Y. C.; Guo, X.; Liu, X. F.; Shang, J. X.; Shui, J. L. Catalysis stability enhancement of Fe/Co dual-atom site via phosphorus coordination for proton exchange membrane fuel cell. Nano Res. 2022, 15, 3082–3089.
Gao, X. B.; Wang, Y. C.; Xu, W. C.; Huang, H.; Zhao, K. M.; Ye, H.; Zhou, Z. Y.; Zheng, N. F.; Sun, S. G. Mechanism of particle-mediated inhibition of demetalation for single-atom catalytic sites in acidic electrochemical environments. J. Am. Chem. Soc. 2023, 145, 15528–15537.
Jaleh, B.; Nasrollahzadeh, M.; Eslamipanah, M.; Nasri, A.; Shabanlou, E.; Manwar, N. R.; Zboril, R.; Fornasiero, P.; Gawande, M. B. The role of carbon-based materials for fuel cells performance. Carbon 2022, 198, 301–352.
You, P. Y.; Kamarudin, S. K. Recent progress of carbonaceous materials in fuel cell applications: An overview. Chem. Eng. J. 2017, 309, 489–502.
Borup, R.; Meyers, J.; Pivovar, B.; Kim, Y. S.; Mukundan, R.; Garland, N.; Myers, D.; Wilson, M.; Garzon, F.; Wood, D. et al. Scientific aspects of polymer electrolyte fuel cell durability and degradation. Chem. Rev. 2007, 107, 3904–3951.
Shao, Y. Y.; Dodelet, J. P.; Wu, G.; Zelenay, P. PGM-free cathode catalysts for PEM fuel cells: A mini-review on stability challenges. Adv. Mater. 2019, 31, 1807615.
Dubau, L.; Castanheira, L.; Maillard, F.; Chatenet, M.; Lottin, O.; Maranzana, G.; Dillet, J.; Lamibrac, A.; Perrin, J. C.; Moukheiber, E. et al. A review of PEM fuel cell durability: Materials degradation, local heterogeneities of aging and possible mitigation strategies. WIREs Energy Environ. 2014, 3, 540–560.
Wang, W.; Luo, J.; Chen, S. L. Carbon oxidation reactions could misguide the evaluation of carbon black-based oxygen-evolution electrocatalysts. Chem. Commun. 2017, 53, 11556–11559.
Zhang, G. X.; Chenitz, R.; Lefèvre, M.; Sun, S. H.; Dodelet, J. P. Is iron involved in the lack of stability of Fe/N/C electrocatalysts used to reduce oxygen at the cathode of PEM fuel cells. Nano Energy 2016, 29, 111–125.
Xie, X. H.; He, C.; Li, B. Y.; He, Y. H.; Cullen, D. A.; Wegener, E. C.; Kropf, A. J.; Martinez, U.; Cheng, Y. W.; Engelhard, M. H. et al. Performance enhancement and degradation mechanism identification of a single-atom Co–N–C catalyst for proton exchange membrane fuel cells. Nat. Catal. 2020, 3, 1044–1054.
Avasarala, B.; Moore, R.; Haldar, P. Surface oxidation of carbon supports due to potential cycling under PEM fuel cell conditions. Electrochim. Acta 2010, 55, 4765–4771.
Martinaiou, I.; Shahraei, A.; Grimm, F.; Zhang, H. B.; Wittich, C.; Klemenz, S.; Dolique, S. J.; Kleebe, H. J.; Stark, R. W.; Kramm, U. I. Effect of metal species on the stability of Me–N–C catalysts during accelerated stress tests mimicking the start-up and shut-down conditions. Electrochim. Acta 2017, 243, 183–196.
Goellner, V.; Baldizzone, C.; Schuppert, A.; Sougrati, M. T.; Mayrhofer, K.; Jaouen, F. Degradation of Fe/N/C catalysts upon high polarization in acid medium. Phys. Chem. Chem. Phys. 2014, 16, 18454–18462.
Barb, W. G.; Baxendale, J. H.; George, P.; Hargrave, K. R. Reactions of ferrous and ferric ions with hydrogen peroxide. Nature 1949, 163, 692–694.
Choi, C. H.; Lim, H. K.; Chung, M. W.; Chon, G.; Sahraie, N. R.; Altin, A.; Sougrati, M. T.; Stievano, L.; Oh, H. S.; Park, E. S. et al. The Achilles’ heel of iron-based catalysts during oxygen reduction in an acidic medium. Energy Environ. Sci. 2018, 11, 3176–3182.
Goellner, V.; Armel, V.; Zitolo, A.; Fonda, E.; Jaouen, F. Degradation by hydrogen peroxide of metal-nitrogen-carbon catalysts for oxygen reduction. J. Electrochem. Soc. 2015, 162, H403–H414.
Kumar, K.; Dubau, L.; Mermoux, M.; Li, J. K.; Zitolo, A.; Nelayah, J.; Jaouen, F.; Maillard, F. On the influence of oxygen on the degradation of Fe–N–C catalysts. Angew. Chem., Int. Ed. 2020, 59, 3235–3243.
He, Y. H.; Guo, H.; Hwang, S.; Yang, X. X.; He, Z. Z.; Braaten, J.; Karakalos, S.; Shan, W. T.; Wang, M. Y.; Zhou, H. et al. Single cobalt sites dispersed in hierarchically porous nanofiber networks for durable and high-power PGM-free cathodes in fuel cells. Adv. Mater. 2020, 32, 2003577.
Li, L. F.; Wen, Y. D.; Han, G. K.; Kong, F. P.; Du, L.; Ma, Y. L.; Zuo, P. J.; Du, C. Y.; Yin, G. P. Architecting FeN x on high graphitization carbon for high-performance oxygen reduction by regulating d-band center. Small 2023, 19, 2300758.
Yu, J. M.; Su, C. L.; Shang, L.; Zhang, T. R. Single-atom-based oxygen reduction reaction catalysts for proton exchange membrane fuel cells: Progress and perspective. ACS Nano 2023, 17, 19514–19525.
Gu, W. L.; Xu, J. B.; Sun, J.; Zhao, T. S. A durable and robust Fe–N–C electrocatalyst for oxygen reduction reactions by introducing Ti3C2–TiO2 as radical scavengers. Int. J. Hydrogen Energy 2023, 48, 5323–5332.
Chu, Y. Y.; Luo, E. G.; Wei, Y.; Zhu, S. Y.; Wang, X.; Yang, L. T.; Gao, N. X.; Wang, Y.; Jiang, Z.; Liu, C. P. et al. Dual single-atom catalyst design to build robust oxygen reduction electrode via free radical scavenging. Chem Catal. 2023, 3, 100532.
Xie, H.; Xie, X. H.; Hu, G. X.; Prabhakaran, V.; Saha, S.; Gonzalez-Lopez, L.; Phakatkar, A. H.; Hong, M.; Wu, M. L.; Shahbazian-Yassar, R. et al. Ta–TiO x nanoparticles as radical scavengers to improve the durability of Fe–N–C oxygen reduction catalysts. Nat. Energy 2022, 7, 281–289.
Wan, X.; Shui, J. L. Exploring durable single-atom catalysts for proton exchange membrane fuel cells. ACS Energy Lett. 2022, 7, 1696–1705.
Choi, J. Y.; Yang, L. J.; Kishimoto, T.; Fu, X. G.; Ye, S. Y.; Chen, Z. W.; Banham, D. Is the rapid initial performance loss of Fe/N/C non precious metal catalysts due to micropore flooding. Energy Environ. Sci. 2017, 10, 296–305.
Wang, W.; Jia, Q. Y.; Mukerjee, S.; Chen, S. L. Recent insights into the oxygen-reduction electrocatalysis of Fe/N/C materials. ACS Catal. 2019, 9, 10126–10141.
Yang, L. J.; Larouche, N.; Chenitz, R.; Zhang, G. X.; Lefèvre, M.; Dodelet, J. P. Activity, performance, and durability for the reduction of oxygen in PEM fuel cells, of Fe/N/C electrocatalysts obtained from the pyrolysis of metal-organic-framework and iron porphyrin precursors. Electrochim. Acta 2015, 159, 184–197.
Wang, Y. C.; Huang, L.; Zhang, P.; Qiu, Y. T.; Sheng, T.; Zhou, Z. Y.; Wang, G.; Liu, J. G.; Rauf, M.; Gu, Z. Q. et al. Constructing a triple-phase interface in micropores to boost performance of Fe/N/C catalysts for direct methanol fuel cells. ACS Energy Lett. 2017, 2, 645–650.
Liu, G.; Li, X. G.; Lee, J. W.; Popov, B. N. A review of the development of nitrogen-modified carbon-based catalysts for oxygen reduction at USC. Catal. Sci. Technol. 2011, 1, 207–217.
Banham, D.; Ye, S. Y.; Pei, K. T.; Ozaki, J. I.; Kishimoto, T.; Imashiro, Y. A review of the stability and durability of non-precious metal catalysts for the oxygen reduction reaction in proton exchange membrane fuel cells. J. Power Sources 2015, 285, 334–348.
Herranz, J.; Jaouen, F.; Lefèvre, M.; Kramm, U. I.; Proietti, E.; Dodelet, J. P.; Bogdanoff, P.; Fiechter, S.; Abs-Wurmbach, I.; Bertrand, P. et al. Unveiling N-protonation and anion-binding effects on Fe/N/C catalysts for O2 reduction in proton-exchange-membrane fuel cells. J. Phys. Chem. C 2011, 115, 16087–16097.
Strickland, K.; Pavlicek, R.; Miner, E.; Jia, Q. Y.; Zoller, I.; Ghoshal, S.; Liang, W. T.; Mukerjee, S. Anion resistant oxygen reduction electrocatalyst in phosphoric acid fuel cell. ACS Catal. 2018, 8, 3833–3843.
Tylus, U.; Jia, Q.; Hafiz, H.; Allen, R. J.; Barbiellini, B.; Bansil, A.; Mukerjee, S. Engendering anion immunity in oxygen consuming cathodes based on Fe–N x electrocatalysts: Spectroscopic and electrochemical advanced characterizations. Appl. Catal.: B Environ. 2016, 198, 318–324.
Yang, N.; Peng, L. L.; Li, L.; Li, J.; Liao, Q.; Shao, M. H.; Wei, Z. D. Theoretically probing the possible degradation mechanisms of an FeNC catalyst during the oxygen reduction reaction. Chem. Sci. 2021, 12, 12476–12484.
Liu, L. C.; Corma, A. Evolution of isolated atoms and clusters in catalysis. Trends Chem. 2020, 2, 383–400.
Nie, L.; Mei, D. H.; Xiong, H. F.; Peng, B.; Ren, Z. B.; Hernandez, X. I. P.; DeLaRiva, A.; Wang, M.; Engelhard, M. H.; Kovarik, L. et al. Activation of surface lattice oxygen in single-atom Pt/CeO2 for low-temperature CO oxidation. Science 2017, 358, 1419–1423.
Lai, W. H.; Zhang, B. W.; Hu, Z. P.; Qu, X. M.; Jiang, Y. X.; Wang, Y. X.; Wang, J. Z.; Liu, H. K.; Chou, S. L. The quasi-Pt-allotrope catalyst: Hollow PtCo@single-atom Pt1 on nitrogen-doped carbon toward superior oxygen reduction. Adv. Funct. Mater. 2019, 29, 1807340.
Yang, H. Q.; Li, Z. Y.; Kou, S. Q.; Lu, G. L.; Liu, Z. N. A complex-sequestered strategy to fabricate Fe single-atom catalyst for efficient oxygen reduction in a broad pH-range. Appl. Catal.: B Environ. 2020, 278, 119270.
Yang, K. C.; Ma, H. L.; Ren, R. J.; Xiao, L.; Jiang, W. Y.; Xie, Y.; Wang, G. W.; Lu, J. T.; Zhuang, L. Multidimensional electrochemistry decodes the operando mechanism of hydrogen oxidation. Angew. Chem., Int. Ed. 2024, 63, e202318389.
Guo, Z. F.; Ga, L.; Liu, M.; Ai, J. Progress in metal-organic frameworks for small molecule oxidative coupled hydrogen production. Chem. Eng. J. 2024, 480, 148365.
Quan, J. X.; Miao, Z. W.; Lin, Y. S.; Lv, J.; Liu, H. L.; Feng, C. Z.; Jiang, E. C.; Hu, Z. F. Agglomeration mechanism of Fe2O3/Al2O3 oxygen carrier in chemical looping gasification. Energy 2023, 284, 129200.
Thorarinsdottir, A. E.; Erdosy, D. P.; Costentin, C.; Mason, J. A.; Nocera, D. G. Enhanced activity for the oxygen reduction reaction in microporous water. Nat. Catal. 2023, 6, 425–434.
Sun, H. X.; Wang, J. J.; Zhu, Z. Q.; Li, A. Carbon-based electrocatalyst derived from porous organic polymer in oxygen reduction reaction for fuel cells. Prog. Chem. 2023, 35, 1638–1654.
Chen, W. X.; Pei, J. J.; He, C. T.; Wan, J. W.; Ren, H. L.; Wang, Y.; Dong, J. C.; Wu, K. L.; Cheong, W. C.; Mao, J. J. et al. Single tungsten atoms supported on MOF-derived N-doped carbon for robust electrochemical hydrogen evolution. Adv. Mater. 2018, 30, 1800396.
Liu, W. G.; Zhang, L. L.; Liu, X.; Liu, X. Y.; Yang, X. F.; Miao, S.; Wang, W. T.; Wang, A. Q.; Zhang, T. Discriminating catalytically active FeN x species of atomically dispersed Fe–N–C catalyst for selective oxidation of the C–H bond. J. Am. Chem. Soc. 2017, 139, 10790–10798.
Yin, S. H.; Yang, S. L.; Li, G.; Li, G.; Zhang, B. W.; Wang, C. T.; Chen, M. S.; Liao, H. G.; Yang, J.; Jiang, Y. X. et al. Seizing gaseous Fe2+ to densify O2-accessible Fe–N4 sites for high-performance proton exchange membrane fuel cells. Energy Environ. Sci. 2022, 15, 3033–3040.
Miao, J.; Zhu, Y.; Lang, J. Y.; Zhang, J. Z.; Cheng, S. X.; Zhou, B. X.; Zhang, L. Z.; Alvarez, P. J. J.; Long, M. C. Spin-state-dependent peroxymonosulfate activation of single-atom M–N moieties via a radical-free pathway. ACS Catal. 2021, 11, 9569–9577.
Zhong, W. H.; Qiu, Y.; Shen, H. J.; Wang, X. J.; Yuan, J. Y.; Jia, C. Y.; Bi, S. W.; Jiang, J. Electronic spin moment as a catalytic descriptor for Fe single-atom catalysts supported on C2N. J. Am. Chem. Soc. 2021, 143, 4405–4413.
Xiao, M. L.; Gao, L. Q.; Wang, Y.; Wang, X.; Zhu, J. B.; Jin, Z.; Liu, C. P.; Chen, H. Q.; Li, G. R.; Ge, J. J. et al. Engineering energy level of metal center: Ru single-atom site for efficient and durable oxygen reduction catalysis. J. Am. Chem. Soc. 2019, 141, 19800–19806.
Wei, P. J.; Yu, G. Q.; Naruta, Y.; Liu, J. G. Covalent grafting of carbon nanotubes with a biomimetic heme model compound to enhance oxygen reduction reactions. Angew. Chem., Int. Ed. 2014, 53, 6659–6663.
Lai, Q. X.; Zheng, L. R.; Liang, Y. Y.; He, J. P.; Zhao, J. X.; Chen, J. H. Metal-organic-framework-derived Fe–N/C electrocatalyst with five-coordinated Fe–N x sites for advanced oxygen reduction in acid media. ACS Catal. 2017, 7, 1655–1663.
Chen, Z. G.; Gong, W. B.; Liu, Z. B.; Cong, S.; Zheng, Z. H.; Wang, Z.; Zhang, W.; Ma, J. Y.; Yu, H. S.; Li, G. H. et al. Coordination-controlled single-atom tungsten as a non-3D-metal oxygen reduction reaction electrocatalyst with ultrahigh mass activity. Nano Energy 2019, 60, 394–403.
Wu, X.; Zhang, H. B.; Zuo, S. W.; Dong, J. C.; Li, Y.; Zhang, J.; Han, Y. Engineering the coordination sphere of isolated active sites to explore the intrinsic activity in single-atom catalysts. Nano-Micro Lett. 2021, 13, 136.
Li, Z. G.; Chen, J. B.; Guo, Y. J.; Zheng, F. X.; Qu, K. G.; Wang, L.; Li, R.; Xiong, S. L.; Kang, W. J.; Li, H. B. Interfacial oxygen atom modification of a PdSn alloy to boost oxygen reduction in zinc-air batteries. J. Colloid Interface Sci. 2024, 659, 257–266.
Jones, J.; Xiong, H. F.; DeLaRiva, A. T.; Peterson, E. J.; Pham, H.; Challa, S. R.; Qi, G.; Oh, S.; Wiebenga, M. H.; Pereira Hernández, X. I. et al. Thermally stable single-atom platinum-on-ceria catalysts via atom trapping. Science 2016, 353, 150–154.
Shen, H. J.; Gracia-Espino, E.; Ma, J. Y.; Zang, K. T.; Luo, J.; Wang, L.; Gao, S. S.; Mamat, X.; Hu, G. Z.; Wagberg, T. et al. Synergistic effects between atomically dispersed Fe–N–C and C–S–C for the oxygen reduction reaction in acidic media. Angew. Chem., Int. Ed. 2017, 56, 13800–13804.
Chen, Y. J.; Ji, S. F.; Zhao, S.; Chen, W. X.; Dong, J. C.; Cheong, W. C.; Shen, R. A.; Wen, X. D.; Zheng, L. R.; Rykov, A. I. et al. Enhanced oxygen reduction with single-atomic-site iron catalysts for a zinc-air battery and hydrogen-air fuel cell. Nat. Commun. 2018, 9, 5422.
Guo, L.; Hwang, S.; Li, B. Y.; Yang, F.; Wang, M. Y.; Chen, M. J.; Yang, X. X.; Karakalos, S. G.; Cullen, D. A.; Feng, Z. X. et al. Promoting atomically dispersed MnN4 sites via sulfur doping for oxygen reduction: Unveiling intrinsic activity and degradation in fuel cells. ACS Nano 2021, 15, 6886–6899.
Ding, S. C.; Barr, J. A.; Shi, Q. R.; Zeng, Y. C.; Tieu, P.; Lyu, Z. Y.; Fang, L. Z.; Li, T.; Pan, X. Q.; Beckman, S. P. et al. Engineering atomic single metal-FeN4Cl sites with enhanced oxygen-reduction activity for high-performance proton exchange membrane fuel cells. ACS Nano 2022, 16, 15165–15174.
Yang, G. G.; Zhu, J. W.; Yuan, P. F.; Hu, Y. F.; Qu, G.; Lu, B. A.; Xue, X. Y.; Yin, H. B.; Cheng, W. Z.; Cheng, J. Q. et al. Regulating Fe-spin state by atomically dispersed Mn–N in Fe–N–C catalysts with high oxygen reduction activity. Nat. Commun. 2021, 12, 1734.
Li, H. G.; Di, S. L.; Niu, P.; Wang, S. L.; Wang, J.; Li, L. A durable half-metallic diatomic catalyst for efficient oxygen reduction. Energy Environ. Sci. 2022, 15, 1601–1610.
Ao, X.; Zhang, W.; Zhao, B. T.; Ding, Y.; Nam, G.; Soule, L.; Abdelhafiz, A.; Wang, C. D.; Liu, M. L. Atomically dispersed Fe–N–C decorated with Pt-alloy core-shell nanoparticles for improved activity and durability towards oxygen reduction. Energy Environ. Sci. 2020, 13, 3032–3040.
Luo, Y.; Li, K.; Chen, Y. T.; Feng, J. Z.; Wang, L. K.; Jiang, Y. G.; Li, L. J.; Yu, G.; Feng, J. Single-atom and hierarchical-pore aerogel confinement strategy for low-platinum fuel cells. Adv. Mater. 2023, 35, 2300624.
Jiang, M.; Wang, F.; Yang, F.; He, H.; Yang, J.; Zhang, W.; Luo, J. Y.; Zhang, J.; Fu, C. P. Rationalization on high-loading iron and cobalt dual metal single atoms and mechanistic insight into the oxygen reduction reaction. Nano Energy 2022, 93, 106793.
Wang, J.; Huang, Z. Q.; Liu, W.; Chang, C. R.; Tang, H. L.; Li, Z. J.; Chen, W. X.; Jia, C. J.; Yao, T.; Wei, S. Q. et al. Design of N-coordinated dual-metal sites: A stable and active Pt-free catalyst for acidic oxygen reduction reaction. J. Am. Chem. Soc. 2017, 139, 17281–17284.
Lu, Z. Y.; Wang, B.; Hu, Y. F.; Liu, W.; Zhao, Y. F.; Yang, R. O.; Li, Z. P.; Luo, J.; Chi, B.; Jiang, Z. et al. An isolated zinc-cobalt atomic pair for highly active and durable oxygen reduction. Angew. Chem., Int. Ed. 2019, 58, 2622–2626.
Fu, X. G.; Gao, R.; Jiang, G. P.; Li, M.; Li, S.; Luo, D.; Hu, Y. F.; Yuan, Q. X.; Huang, W. X.; Zhu, N. et al. Evolution of atomic-scale dispersion of FeN x in hierarchically porous 3D air electrode to boost the interfacial electrocatalysis of oxygen reduction in PEMFC. Nano Energy 2021, 83, 105734.
Yi, S. Y.; Choi, E.; Jang, H. Y.; Lee, S.; Park, J.; Choi, D.; Jang, Y.; Kang, H.; Back, S.; Jang, S. et al. Insight into defect engineering of atomically dispersed iron electrocatalysts for high-performance proton exchange membrane fuel cell. Adv. Mater. 2023, 35, 2302666.
Jin, C. Q.; Liao, Y. C.; Zhang, A. J.; Zhao, S. Q.; Wang, R.; Li, J. S.; Tang, H. L. Low-Pt anodes with gradient molybdenum isomorphism for high performance and anti-CO poisoning PEMFCs. Nano Energy 2024, 122, 109305.
Jiao, L.; Zhang, R.; Wan, G.; Yang, W. J.; Wan, X.; Zhou, H.; Shui, J. L.; Yu, S. H.; Jiang, H. L. Nanocasting SiO2 into metal-organic frameworks imparts dual protection to high-loading Fe single-atom electrocatalysts. Nat. Commun. 2020, 11, 2831.
Yang, H.; Wang, X.; Zheng, T.; Cuello, N. C.; Goenaga, G.; Zawodzinski, T. A.; Tian, H.; Wright, J. T.; Meulenberg, R. W.; Wang, X. K. et al. CrN-encapsulated hollow Cr–N–C capsules boosting oxygen reduction catalysis in PEMFC. CCS Chem. 2021, 3, 208–218.
Miao, Z. P.; Xia, Y.; Liang, J. S.; Xie, L. F.; Chen, S. Q.; Li, S. Z.; Wang, H. L.; Hu, S.; Han, J. T.; Li, Q. Constructing Co–N–C catalyst via a double crosslinking hydrogel strategy for enhanced oxygen reduction catalysis in fuel cells. Small 2021, 17, 2100735.
Kong, F. P.; Si, R. T.; Chen, N.; Wang, Q.; Li, J. J.; Yin, G. P.; Gu, M.; Wang, J. J.; Liu, L. M.; Sun, X. L. Origin of hetero-nuclear Au–Co dual atoms for efficient acidic oxygen reduction. Appl. Catal.: B Environ. 2022, 301, 120782.
An, L.; Chi, B.; Deng, Y. J.; Chen, C.; Deng, X. H.; Zeng, R. J.; Zheng, Y. Y.; Dang, D.; Yang, X.; Tian, X. L. Engineering g–C3N4 composited Fe-UIO-66 to in situ generate robust single-atom Fe sites for high-performance PEMFC and Zn-air battery. J. Mater. Chem. A 2023, 11, 118–129.
Xue, D. P.; Yuan, P. F.; Jiang, S.; Wei, Y. F.; Zhou, Y.; Dong, C. L.; Yan, W. F.; Mu, S. C.; Zhang, J. N. Altering the spin state of Fe–N–C through ligand field modulation of single-atom sites boosts the oxygen reduction reaction. Nano Energy 2023, 105, 108020.
Quartarone, E.; Angioni, S.; Mustarelli, P. Polymer and composite membranes for proton-conducting, high-temperature fuel cells: A critical review. Materials 2017, 10, 687.
Üregen, N.; Pehlivanoğlu, K.; Özdemir, Y.; Devrim, Y. Development of polybenzimidazole/graphene oxide composite membranes for high temperature PEM fuel cells. Int. J. Hydrogen Energy 2017, 42, 2636–2647.
Jia, T. T.; Shen, S.; Zhao, J.; Jin, J.; Pan, B.; Duan, X. Q.; Meng, C. X.; Che, Q. T. Ultrathin membranes formation via the layer by layer self-assembly of carbon nanotubes-based inorganics as high temperature proton exchange membranes. Int. J. Hydrogen Energy 2020, 45, 14517–14527.
Escorihuela, J.; Sahuquillo, Ó.; García-Bernabé, A.; Giménez, E.; Compañ, V. Phosphoric acid doped polybenzimidazole (PBI)/zeolitic imidazolate framework composite membranes with significantly enhanced proton conductivity under low humidity conditions. Nanomaterials 2018, 8, 775.
Zhang, Q.; Liu, H.; Li, X.; Xu, R.; Zhong, J.; Chen, R. Y.; Gu, X. H. Synthesis and characterization of polybenzimidazole/α-zirconium phosphate composites as proton exchange membrane. Polym. Eng. Sci. 2016, 56, 622–628.
Chen, L.; Lin, R.; Tang, S. H.; Zhong, D.; Hao, Z. X. Structural design of gas diffusion layer for proton exchange membrane fuel cell at varying humidification. J. Power Sources 2020, 467, 228355.
Simon, C.; Endres, J.; Nefzger-Loders, B.; Wilhelm, F.; Gasteiger, H. A. Interaction of pore size and hydrophobicity/hydrophilicity for improved oxygen and water transport through microporous layers. J. Electrochem. Soc. 2019, 166, F1022.
Wu, R.; Zhu, X.; Liao, Q.; Wang, H.; Ding, Y. D.; Li, J.; Ye, D. D. Determination of oxygen effective diffusivity in porous gas diffusion layer using a three-dimensional pore network model. Electrochim. Acta 2010, 55, 7394–7403.
Tawfik, H.; El-Khatib, K.; Hung, Y.; Mahajan, D. Effects of bipolar plate material and impurities in reactant gases on PEM fuel cell performance. Ind. Eng. Chem. Res. 2007, 46, 8898–8905.