Electrochemical co-upgrading CO₂ and glycerol for selective formate production with 190% overall Faradaic efficiency

Dingwen Chen^{¹^,^§}, Siheng Yang^{¹^,^§}, Jing Gao^{²^,^§}, Xuan Zheng^¹, Jiawei Mao^³, Qinyuan Hu^⁴, Xiaohan Sun^⁵, Li Ji^⁶, Xueli Zheng^¹, Haiyan Fu^¹, Weichao Xue^¹, Hua Chen^¹, Shuang Li^⁷, Chong Cheng^⁷, Jing Peng^⁸, Xingchen Jiao^⁴, Ruixiang Li^¹

(), Michael Grätzel^²

(), Jiaqi Xu^{¹^,²}

()

1Key Laboratory of Green Chemistry & Technology of Ministry of Education, College of Chemistry, Sichuan University, Chengdu 610064, China

2Laboratory of Photonics and Interfaces, École Polytechnique Fédérale de Lausanne, 1015 Lausanne, Switzerland

3Sichuan Institute of Product Quality Supervision and Inspection, Chengdu 610100, China

4Key Laboratory of Synthetic and Biological Colloids, Ministry of Education, School of Chemical and Material Engineering, Jiangnan University, Wuxi 214122, China

5Key Laboratory of Bio-Based Material Science and Technology of Ministry of Education, Northeast Forestry University, Harbin 150040, China

6Sichuan Research Institute of Chemical Quality and Safety Testing, Chengdu 610031, China

7College of Polymer Science and Engineering, State Key Laboratory of Polymer Materials Engineering, Sichuan University, Chengdu 610065, China

8Faculty of Materials Science and Energy Engineering/Institute of Technology for Carbon Neutrality, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen 518055, China

^§ Dingwen Chen, Siheng Yang, and Jing Gao contributed equally to this work.

Show Author Information

Graphical Abstract

View original image Download original image

To reduce energy consumption and enhance the economic viability of carbon dioxide (CO₂) electrolysis systems, replacing the anodic oxygen evolution reaction (OER) with the glycerol oxidation reaction (GOR) has emerged as a promising approach. To this end, an efficient GOR//CO₂ reduction reaction (CO₂RR) paired electrolysis system has been developed using NiOOH@Ni₃S₂/ nickel foam (NF) and defect-rich bismuth nanosheets as catalysts, achieving a state-of-the-art total formate Faradaic efficiency of ca. 190% at 160 mA·cm⁻² and offering a novel strategy for the co-upgrading of CO₂ and biomass.

Abstract

The overall energy efficiency (EE) is critical for commercializing promising electrochemical technologies, such as the carbon dioxide reduction reaction (CO₂RR). Despite the rapid development of advanced catalysts and reactors for CO₂RR, its commercial potential is still hindered by the sluggish oxygen evolution reaction (OER), which causes high cell voltages and low EEs. Herein, we developed a NiOOH@Ni₃S₂ catalyst on the surface of nickel foam (NF) via an electrochemical surface reconstruction strategy. We observed that the oxidation of glycerol (GLY) to formate (FA) is more thermodynamically favorable than the OER on the developed NiOOH@Ni₃S₂/NF catalysts. The Ni²⁺/Ni³⁺ redox couples within the NiOOH@Ni₃S₂ heterojunction enhance the charge transfer kinetics between the active sites and adsorbed reaction intermediates, facilitating the highly selective and active generation of FA from GLY oxidation reaction (GOR), with a remarkable Faradaic efficiency (FE) of 94% achieved at 100 mA·cm⁻². Comprehensive mechanistic studies identified that the reaction pathway towards FA generation starts from glyceraldehyde intermediates, and glycolate was considered as the key species. Moreover, benefiting from the efficient conversion of CO₂ to FA on bismuth nanosheets, the GOR//CO₂RR paired electrolysis system realizes a remarkable overall FE of ca. 190% for FA co-production at 160 mA·cm⁻² (cathodic FE: 91.25% and anodic FE: 98.70%). This proceeds at a cell voltage of ca. 2.32 V, which is ca. 0.85 V lower than that of OER-assisted CO₂RR system at the same current density. This work provides new insights for co-upgrading CO₂ and biomass to value-added chemicals.

Keywords

CO₂ electroreduction glycerol electrooxidation formate production co-electrolysis system biomass conversion

Electronic Supplementary Material

Download File(s)

7399_ESM.pdf (7.3 MB)

References

[1]

Das, P.; Mathur, J.; Bhakar, R.; Kanudia, A. Implications of short-term renewable energy resource intermittency in long-term power system planning. Energy Strategy Rev. 2018, 22, 1–15.

Electrochemical co-upgrading CO2 and glycerol for selective formate production with 190% overall Faradaic efficiency