▎ 摘　　要

Photoreduction of CO2 into fuel molecules such as CH4 represents a promising route to simultaneously explore renewable energy and alleviate global warming. However, the implementation of such a process is hampered by low product yields and poor selectivity. A 2D/2D heterojunction of ultrathin SiC and reduced graphene oxide (RGO) nanosheets was fabricated in situ for efficient and selective photoreduction of CO2. Ultrathin SiC suppresses significant charge recombination in the bulk phase, thus providing more energetic electrons. The robust 2D/2D heterojunction allows fast transfer of energetic electrons from SiC to RGO. Combining the vital role of RGO in facilitating CO2 activation, the optimized SiC/RGO exhibits an electron-transfer rate of 58.17 mu mol h(-1) g(-1) towards CO2 reduction, 2.7 times that of pure SiC (20.25 mu mol h(-1) g(-1)). About 92 % of the transferred electrons from SiC are devoted to generating CH4 (6.72 mu mol h(-1) g(-1)). Such high efficiency and selectivity are mainly a result of the densely accumulated energetic electrons within RGO, which facilitate the eight-electron process to produce CH4. This work will inspire the design of catalyst/cocatalyst systems for efficient and selective photoreduction of CO2.