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Electroreduction of CO 2 to CH 4 without overpotential using Pt‐black catalysts: Enhancement of faradaic efficiency
Author(s) -
Matsuda Shofu,
Yoshida Yuta,
Umeda Minoru
Publication year - 2022
Publication title -
international journal of energy research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.808
H-Index - 95
eISSN - 1099-114X
pISSN - 0363-907X
DOI - 10.1002/er.7836
Subject(s) - overpotential , faraday efficiency , electrocatalyst , chemistry , electrolysis , carbon black , electrolyte , catalysis , chemical engineering , inorganic chemistry , materials science , electrochemistry , electrode , organic chemistry , natural rubber , engineering
Summary The use of metal electrocatalysts (Cu, Au, and Ag) is the mainstream in primary CO 2 reduction systems, but their large overpotential induces a decrease in energy conversion efficiency. Recently, it has been discovered that carbon‐supported Pt can make a game change to reduce CO 2 to CH 4 electrocatalytically without overpotential; however, its faradaic efficiency remains only 12.3% thus far. One approach is to investigate the role of carbon supports for improving the efficiency. In this study, improved CO 2 reduction was carried out by employing a Pt‐black electrocatalyst without a carbon support in a polymer electrolyte membrane electrolyzer cell. When supplying CO 2 diluted by Ar gas at CO 2 concentrations of 4‐7 vol.%, the efficient CH 4 generation was observed. The reason behind the improved production of CH 4 occurs by a Langmuir‐Hinshelwood mechanism associated with adsorbed CO (CO ads ) and H (H ads ) on the Pt electrocatalyst. Moreover, a high‐density CO ads environment (surface) can be created at the Pt‐black catalyst, achieving CH 4 generation with a faradaic efficiency of 23.2% at 0.18 V vs RHE. Therefore, this study succeeded in improving the faradaic efficiency of CH 4 production from CO 2 reduction without overpotential using a Pt‐black electrocatalyst.