Stable Aqueous Photoelectrochemical CO2 Reduction by a Cu2O Dark Cathode with Improved Selectivity for Carbonaceous Products

详细信息    查看全文

• 作者：Xiaoxia Chang ; Dr. Tuo Wang ; Dr. Peng Zhang ; Yijia Wei ; Jiubing Zhao and Prof. Dr. Jinlong Gong
• 刊名：Angewandte Chemie International Edition
• 出版年：2016
• 出版时间：July 25, 2016
• 年：2016
• 卷：55
• 期：31
• 页码：8840-8845
• 全文大小：2374K
• ISSN：1521-3773

文摘

Photocatalytic reduction of CO₂ to produce fuels is a promising way to reduce CO₂ emission and address the energy crisis. However, the H₂ evolution reaction competes with CO₂ photoreduction, which would lower the overall selectivity for carbonaceous products. Cu₂O has emerged as a promising material for suppressing the H₂ evolution. However, it suffers from poor stability, which is commonly regarded as the result of the electron-induced reduction of Cu₂O. This paper describes a simple strategy using Cu₂O as a dark cathode and TiO₂ as a photoanode to achieve stable aqueous CO₂ reduction with a high Faradaic efficiency of 87.4 % and a selectivity of 92.6 % for carbonaceous products. We have shown that the photogenerated holes, instead of the electrons, primarily account for the instability of Cu₂O. Therefore, Cu₂O was used as a dark cathode to minimize the adverse effects of holes, by which an improved stability was achieved compared to the Cu₂O photocathode under illumination. Additionally, direct exposure of the Cu₂O surface to the electrolyte was identified as a critical factor for the high selectivity for carbonaceous products.