Three-Dimensional Nitrogen-Doped Graphene Aerogel-Supported MnO Nanoparticles as Efficient Electrocatalysts for CO₂ Reduction to CO

Electrochemical CO 2 reduction reaction (CO 2 RR) is a promising alternative to deal with CO 2 and generate green energy. Carbon monoxide (CO) is one key desired product of the CO 2 RR. Herein, a Mn-based heterogeneous catalyst by depositing MnO nanoparticles on three-dimensional N-doped graphene aerogels (NGAs) is synthesized. The catalyst exhibits a negligible onset potential of −0.27 V (vs RHE). This onset potential is 12.5% lower than that of bulk Au electrodes. Moreover, the higher Faradaic efficiency for CO is 86% at a potential of −0.82 V (vs RHE) and better stability over at least 10 h. The excellent CO 2 RR performance can be attributed to the large specific area of the unique 3D crumpled porous NGA nanostructure, the synergistic effect of well-crystallized MnO active sites, and effective hydrogen evolution reaction suppression from nitrogen doping. The enhancement effect is also revealed by the density functional theory method. Our results highlight a promising new class of low-cost, abundant electrocatalysts for synthetic fuels from CO 2 .