▎ 摘　　要

The chemical transformation of CO2 is an efficient approach in low-carbon energy system. The development of nonprecious metal catalysts with sufficient activity, selectivity, and stability for the generation of CO by CO2 reduction under mild conditions remains a major challenge. A hierarchical architecture catalyst composed of ultrathin graphene shells (2-4 layers) encapsulating homogeneous FeNi alloy nanoparticles shows enhance catalytic performance. Electron transfer from the encapsulated alloy can extend from the inner to the outer shell, resulting in an increased charge density on graphene. Nitrogen atom dopants can synergistically increase the electron density on the catalyst surface and modulate the adsorption capability for acidic CO2 molecules. The optimized FeNi3@NG (NG=N-doped graphene) catalyst, with significant electron penetration through the graphene layer, effects exceptional CO2 conversion of 20.2% with a CO selectivity of nearly 100 %, as well as excellent thermal stability at 523 K.