Selective electrochemical CO reduction over highly porous gold films

• Published in: Journal of materials chemistry. A, Materials for energy and sustainability Vol. 5; no. 41; pp. 21955 - 21964
• Main Authors: Chen, Chengzhen, Zhang, Bo, Zhong, Juhua, Cheng, Zhenmin
• Format: Journal Article
• Published: 24.10.2017
• ISSN: 2050-7488; 2050-7496
• DOI: 10.1039/c7ta04983h

Electrocatalytic reduction of CO 2 to CO is usually subject to the competitive reduction of H + to hydrogen. In this work, it was demonstrated that increasing the local pH at the electrode/electrolyte interface would greatly improve the selectivity for CO 2 reduction to CO by inhibiting hydrogen evolution, resulting in a high CO faradaic efficiency of 90.5%. And this pH-induced effect can be achieved by increasing the thickness of the porous gold film through a facile synthetic technique, based on the enhancement of the mass transfer resistance within the highly porous electrode. Moreover, the thickest film, which had a large electrochemical surface area, displayed a significantly improved catalytic activity for CO 2 reduction at a low overpotential of 390 mV. These results indicate that increasing the local pH by thickening the porous gold film is selective and efficient for electrochemical CO 2 reduction. Electrocatalytic reduction of CO 2 to CO is usually subject to the competitive reduction of H + to hydrogen.