Molecular Catalyst Immobilized Photocathodes for Water/Proton and Carbon Dioxide Reduction.

As one of the components in a tandem photoelectrochemical cell for solar-fuel production, the photocathode carries out the reduction reaction to convert solar light and the corresponding substrate (e.g., proton and CO2) into target fuels. Immobilizing molecular catalysts onto the photocathode is a promising strategy to enhance the interfacial electron/hole-transfer process and to improve the stability of the catalysts. Furthermore, the molecular catalysts are beneficial in improving the selectivity of the reduction reaction, particularly for CO2 reduction. On the photocathode, the binding mode of the catalysts and the arrangement between the photosensitizer and the catalyst also play crucial roles in the performance and stability of the final device. How to firmly and effectively immobilize the catalyst on the photoelectrode is now becoming a scientific question. Recent publications on molecular catalyst immobilized photocathodes are therefore surveyed.