Work

Hydrolysis of Electrolyte Cations Enhances the Electrochemical Reduction of CO 2 over Ag and Cu

Year: 2016

Type: article

Abstract: Electrolyte cation size is known to influence the electrochemical reduction of CO 2 over metals; however, a satisfactory explanation for this phenomenon has not been developed. We report here that these effects can be attributed to a previously unrecognized consequence of cation hydrolysis occurring in the vicinity of the cathode. With increasing cation size, the p K a for cation hydrolysis decreases and is sufficiently low for hydrated K +, Rb +, and Cs + to serve as buffering agents. Buffering lowers the pH near the cathode, leading to an increase in the local concentration of dissolved CO 2 . The consequences of these changes are an increase in cathode activity, a decrease in Faradaic efficiencies for H 2 and CH 4, and an increase in Faradaic efficiencies for CO, C 2 H 4, and C 2 H 5 OH, in full agreement with experimental observations for CO 2 reduction over Ag and Cu.

Source: Journal of the American Chemical Society

DOI: 10.1021/jacs.6b07612

Authors: Meenesh R. Singh, Youngkook Kwon, Yanwei Lum, Joel W. Ager, Alexis T. Bell

Institutions: Lawrence Berkeley National Laboratory, University of Illinois Chicago, Joint Center for Artificial Photosynthesis, Korea Research Institute of Chemical Technology

Language: English

Topic: CO2 Reduction Techniques and Catalysts

Subfield: Renewable Energy, Sustainability and the Environment

Field: Energy

Domain: Physical Sciences

SDG: Climate action

Open Access status: green

Funders: U.S. Department of Energy, Agency for Science, Technology and Research, Office of Science, Basic Energy Sciences