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

作者：Marcel Schreier, Jingshan Luo, Peng Gao, Thomas Moehl, Matthew T. Mayer, Michaël Grätzel · 发表于：Journal of the American Chemical Society · 年份：2016 · DOI：10.1021/jacs.5b12157 · 被引用次数：316 · 研究领域：CO2 Reduction Techniques and Catalysts、Advanced Photocatalysis Techniques、Copper-based nanomaterials and applications

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.