Jun Tae Song, Hyewon Ryoo, Minhyung Cho, Jaehoon Kim, Jun-Gyu Kim, Sung-Yoon Chung, and Jihun Oh
Advanced Energy Materials, dx.doi.org/10.1002/aenm.20161103
An Si photoelectrode with a nanoporous Au thin film for highly selective and efficient photoelectrochemical (PEC) CO2 reduction reaction (CO2RR) is presented. The nanoporous Au thin film is formed by electrochemical reduction of an anodized Au thin film. The electrochemical treatments of the Au thin film critically improve CO2 reduction catalytic activity of Au catalysts and exhibit CO Faradaic efficiency of 96% at 480 mA of overpotential. To apply the electrochemical pretreatment of Au films for PEC CO2RR, a new Si photoelectrode design with mesh-type co-catalysts independently wired at the front and the back of the nanoporous Au mesh and high photovoltage from Si, the Si photoelectrode with the nanoporous au thin film mesh shows conversion of CO2 to CO with 91% Faradaic efficiency at positive potential than the CO2/CO equilibrium potential.