Covalent Immobilization of a Molecular Catalyst on Cu2O Photocathodes for CO2 Reduction

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• 作者：Marcel Schreier ; Jingshan Luo ; Peng Gao ; Thomas Moehl ; Matthew T. Mayer ; Michael Grätzel
• 刊名：Journal of the American Chemical Society
• 出版年：2016
• 出版时间：February 17, 2016
• 年：2016
• 卷：138
• 期：6
• 页码：1938-1946
• 全文大小：496K
• ISSN：1520-5126

文摘

Sunlight-driven CO₂ reduction is a promising way to close the anthropogenic carbon cycle. Integrating light harvester and electrocatalyst functions into a single photoelectrode, which converts solar energy and CO₂ directly into reduced carbon species, is under extensive investigation. The immobilization of rhenium-containing CO₂ reduction catalysts on the surface of a protected Cu₂O-based photocathode allows for the design of a photofunctional unit combining the advantages of molecular catalysts with inorganic photoabsorbers. To achieve large current densities, a nanostructured TiO₂ scaffold, processed at low temperature, was deposited on the surface of protected Cu₂O photocathodes. This led to a 40-fold enhancement of the catalytic photocurrent as compared to planar devices, resulting in the sunlight-driven evolution of CO at large current densities and with high selectivity. Potentiodynamic and spectroelectrochemical measurements point toward a similar mechanism for the catalyst in the bound and unbound form, whereas no significant production of CO was observed from the scaffold in the absence of a molecular catalyst.