The performance of catalyst depends on the intrinsic activity of active sites and the structural characteristics of the support. Here, we simultaneously integrate single nickel (Ni) sites and platinum-nickel (PtNi) alloy nanoparticles (NPs) on a two-dimensional (2D) porous carbon nanosheet, demonstrating remarkable catalytic performance in the oxygen reduction reaction (ORR). The single Ni sites can activate the oxygen molecules into key oxygen-containing intermediate that is further efficiently transferred to the adjacent PtNi alloy NPs and rapidly reduced to H₂O, which establishes a relay catalysis between active sites. The porous structure on the carbon nanosheet support promotes the transfer of active intermediates between these active sites, which assists the relay catalysis by improving mass diffusion. Remarkably, the obtained catalyst demonstrates a half-wave potential of up to 0.942 V, a high mass activity of 0.54 A·mg_Pt⁻¹, and negligible decay of activity after 30,000 cycles, which are all superior to the commercial Pt/C catalysts with comparable loading of Pt. The theoretical calculation results reveal that the obtained catalyst with defect structure of carbon support presents enhanced relay catalytic effect of PtNi alloy NPs and single Ni sites, ultimately realizing improved catalytic performance. This work provides valuable inspiration for developing low platinum loading catalyst, integrating single atoms and alloy with outstanding performance in fuel cell.

Printing techniques hold great potential in the manufacture of electronics such as sensors, micro-supercapacitors, and flexible electronics. However, developing large-scale functional conductive inks with appropriate rheological properties and active components still remains a challenge. Herein, through optimizing the formulations of ink, iron single sites supported N-doped carbon black (Fe₁-NC) inks can serve as both conductive electrodes and high-reactive catalysts to realize convenient glucose detection, which pronouncedly reduces the dosage of enzyme and simplifies the sensors preparation. In detail, utilizing in-situ pyrolysis method, Fe₁-NC single-atom catalysts (SACs) are prepared in bulk (dekagram-level). The batched Fe₁-NC SACs materials can be uniformly mixed with modulated ink to realize the screen printing with high resolution and uniformity. Also, the whole scalable preparation and ink-functional process can be extended to various metals (including Co, Ni, Cu, and Mn). The introduction of highly active Fe₁-NC sites reduces the amount of enzyme used in glucose detection by at least 50%, contributing to the cost reduction of sensors. The strategy in harnessing the SACs onto the carbon inks thus provides a broad prospect for the low-cost and large-scale printing of sensitive sensing devices.

The efficient and rapid removal of volatile organic compounds (VOCs) holds significant importance for ensuring food quality and human health, particularly within the low-temperature confined spaces in refrigerators. However, achieving effective VOCs degradation under such conditions poses challenges in terms of activating inert bonds and facilitating mass transfer. In this study, we propose a novel solution by designing a cleaner module that incorporates 1.07% single Fe atom-anchored manganese dioxide catalysts (FeSAs-MnO₂). The combination of single Fe atoms and defect-rich MnO₂ substrate efficiently activates molecular oxygen, leading to enhanced generation of highly reactive oxygen species (ROS). Non-thermal plasma (NTP) and circulating fan are introduced to facilitate the regeneration of catalytic activity and improve mass transfer. The FeSAs-MnO₂ cleaner module demonstrates exceptional performance in trimethylamine (TMA) removal, achieving a conversion efficiency of 98.9% for 9 ppm within just 9 min. Furthermore, accelerated aging tests predict an extended service life of up to 45 years for the FeSAs-MnO₂ cleaner module, surpassing the expected lifespan of refrigerators significantly.

Acid-stable and highly active catalysts for the electrocatalytic oxygen evolution reaction (OER) are paramount to the advancement of electrochemical technologies for clean energy conversion and utilization. In this work, based on the density functional theory (DFT) calculations, we systematically investigated the MSb₂O₆ (M = Fe, Co, and Ni) and transition metal (TM) doped MSb₂O₆ (TM-MSb₂O₆, TM = Mn, Fe, Co, Ni, Cu, Zn, Ru, Rh, Pd, Ir, and Pt) as potential antimonate-based electrocatalysts for the OER. The stability and OER activity of these considered electrocatalysts were systematically studied under acidic conditions. It was found that Rh-NiSb₂O₆, Pt-CoSb₂O₆, Rh-FeSbO₄, and Co-NiSb₂O₆ can serve as efficient and stable OER electrocatalysts, and their OER catalytic activities are better than that of the current state-of-the-art OER catalyst (IrO₂). Our findings highlight a family of promising antimonate-based OER electrocatalysts for future experimental verification.

Single atom catalysts have been recognized as potential catalysts to fabricate electrochemical biosensors, due to their unexpected catalytic selectivity and activity. Here, we designed and fabricated an ultrasensitive dopamine (DA) sensor based on the flower-like MoS₂ embellished with single Ni site catalyst (Ni-MoS₂). The limit of detection could achieve 1 pM in phosphate buffer solution (PBS, pH = 7.4), 1 pM in bovine serum (pH = 7.4), and 100 pM in artificial urine (pH = 6.8). The excellent sensing performance was attributed to the Ni single atom axial anchoring on the Mo atom in the MoS₂ basal plane with the Ni-S₃ structure. Both the experiment and density functional theory (DFT) results certify that this structural feature is more favorable for the adsorption and electron transfer of DA on Ni atoms. The high proportion of Ni active sites on MoS₂ basal plane effectively enhanced the intrinsic electronic conductivity and electrochemical activity toward DA. The successful establishment of this sensor gives a new guide to expand the field of single atom catalyst in the application of biosensors.

An efficient preparation and local coordination environment regulation of isolated single-atom sites catalysts (ISASC) for improved activity is still challenging. Herein, we develop a solid phase thermal diffusion strategy to synthesize Mn ISASC on highly uniform nitrogen-doped carbon nanotubes by employing MnO₂ nanowires@ZIF-8 core-shell structure. Under high-temperature, the Mn species break free from core-MnO₂ lattice, which will be trapped by carbon defects derived from shell-ZIF-8 carbonization, and immobilized within carbon substrate. Furthermore, the poly-dispersed Mn sites with two nitrogen-coordinated centers can be controllably renovated into four-nitrogen-coordinated Mn sites using NH₃ treatment technology. Both experimental and computational investigations indicate that the symmetric coordinated Mn sites manifest outstanding oxygen reduction activity and superior stability in alkaline and acidic solutions. This work not only provides efficient way to regulate the coordination structure of ISASC to improve catalytic performance but also paves the way to reveal its significant promise for commercial application.

Bacterial infection arised from multipathogenic bacteria is a tricky issue that attracts worldwide attentions. In this paper, a highly accessible copper single-atom catalyst (Cu SAC) supported by biocompatible N-doped mesoporous carbon nanospheres was synthesized with the emulsion-template method. The tightly anchored copper single-atom of the catalyst could effectively transform O₂ into O₂^–• under ambient conditions by the ultra-large pore size (~ 23.80 nm) and small particle size (~ 97.71 nm). Due to multiple synergistically oxidative damages to biomolecules, the Cu SAC could be employed to eliminate different bacteria in vitro without the generation of multidrug resistance (MDR). Moreover, the Cu SAC could also promote wound healing in vivo by eradicating the propagation of bacteria at wound. It is envisioned that the Cu SAC with superior antibacterial performance could be applied in the treatment of related bacterial infection in future.

Developing highly active single-atom sites catalysts for electrochemical reduction of CO₂ is an effective and environmental-friendly strategy to promote carbon-neutral energy cycle and ameliorate global climate issues. Herein, we develop an atomically dispersed N, S co-coordinated bismuth atom sites catalyst (Bi-SAs-NS/C) via a cation and anion simultaneous diffusion strategy for electrocatalytic CO₂ reduction. In this strategy, the bonded Bi cation and S anion are simultaneously diffused into the nitrogen-doped carbon layer in the form of Bi₂S₃. Then Bi is captured by the abundant N-rich vacancies and S is bonded with carbons support at high temperature, formed the N, S co-coordinated Bi sites. Benefiting from the simultaneous diffusion of Bi and S, different electronegative N and S can be effectively co-coordinated with Bi, forming the uniform Bi-N₃S/C sites. The synthesized Bi-SAs-NS/C exhibits a high selectivity towards CO with over 88% Faradaic efficiency in a wide potential range, and achieves a maximum FE_CO of 98.3% at -0.8 V vs. RHE with a current density of 10.24 mA·cm^-2, which can keep constant with negligible degradation in 24 h continuous electrolysis. Experimental results and theoretical calculations reveal that the significantly improved catalytic performance of Bi-SAs-NS/C than Bi-SAs-N/C is ascribed to the replacement of one coordinated-N with low electronegative S in Bi-N₄C center, which can greatly reduce the energy barrier of the intermediate formation in rate-limiting step and increase the reaction kinetics. This work provides an effective strategy for rationally designing highly active single-atom sites catalysts for efficient electrocatalysis with optimized electronic structure.

Metal sulfide based materials as photocatalysts for energy conversion are essential to produce value-added chemical fuels, but their intrinsically slow carrier dynamics and low activity are yet to be resolved. Herein, we developed a unique heterogeneously nanostructured ZnIn₂S₄-CdS heterostructure that involves zero-dimensional (0D) CdS quantum dots uniformly confined on three-dimensional (3D) ZnIn₂S₄ nanoflowers, which achieves an excellent catalytic performance of CO₂ photoconversion under visible-light irradiation. The obtained hierarchical heterostructure can significantly enhance the light harvesting, shorten the migration distance of carriers, and obviously accelerate the transport of electrons. As evidenced by the ultrafast transient absorption spectroscopy, the formed interface can effectively facilitate charge separation and transport. This work opens up a new avenue to carefully design the elaborate heterostructures for achieving optimal charge separation efficiency by lowering interfacial kinetic barriers and energy losses at the interface.

Porous Pt-Fe bimetallic nanocrystals have been synthesized via self-assembly and can effectively facilitate the synthesis of 2-propanol from acetone. The bimetallic catalyst has three-dimensional channels and shows turnover frequencies (TOFs) of up to 972 h^-1 for a continuous process more than 50 h. Preliminary mechanistic studies suggest that the high reactivity is related to the interface consisting of a bimetallic Pt-Fe alloy and Fe₂O_3-x. An understanding of real catalytic behavior and the catalytic mechanism based on model systems has been shown to help fabricate an improved Pt/Fe₃O₄ catalyst with increased activity and lifetime which has great potential for large-scale industrial applications.