▎ 摘　　要

In heterogeneous catalysis, space-confined microenvironment can help to modulate catalytic performance and stabilize reaction intermediates. Recently, two-dimensional (2D) confined catalysis opens a new path for enhancing the performance of catalysts. The restricted space between metal surface and 2D overlayer acts as an ideal environment to promote catalytic reactions. By density functional theory calculations, we reveal the significant effect of graphene overlayer to boost CO2 reduction reaction (CO2RR) on metal surfaces. Graphene overlayer exhibits strong influence on COOH* and CHO*, as well as suppression to the side reaction of HCOOH. With higher Fermi level than the molecules, the graphene overlayer injects electrons into the nonbonding orbitals of COOH* and CHO*, resulting in charge redistribution and electrostatic interaction between molecules and graphene. Such effect reduces reaction free energies and onset potentials of crucial reaction steps. Our findings reveal a new way to the design of catalysts for CO2RR.