▎ 摘　　要

Cuprous oxide (Cu2O) is one of the most promising light-absorbing materials for solar energy conversion, attracting extensive attention in photoelectrochemical carbon dioxide reduction reaction (PEC CO2RR). However, the inefficient collection of photogenerated charge carriers limits the application of Cu2O photocathodes. Herein, adenine biomolecules were introduced into graphene oxide (denoted as A-GO) as a charge transfer layer for coating Cu2O photocathode. The A-GO charge transfer layer can improve photoelectrochemical activity and stability of the Cu2O photocathode by facilitating the electrons transfer. Under AM 1.5 G illumination, the photocurrent density of the A-GO/Cu2O photocathode is 2.74 mA cm(-2) at-1.1 V (vs Ag/AgCl), which is 2.23 and 1.56 times higher than that of bare Cu2O and GO/Cu2O photocathodes, respectively. The Lewis-basic and pyrimidine N sites in adenine biomolecules can assist the Cu2O for PEC CO2RR. During PEC CO2RR, the A-GO/ Cu2O photocathode shows a high Faradaic efficiency of 69.25% for menthol production. Coating biomolecules functionalized GO as a charge transfer layer was a crucial strategy for building effective and stable Cu2O-based photocathodes for PEC CO2RR, as illustrated in this study.