Strong Electronic Coupling Effects at the Heterojunction Interface of SnO₂ Nanodots and g-C₃N₄ for Enhanced CO₂ Electroreduction

Constructing abundant surface/interface structures has significant impacts on improving the performance of electrochemical CO₂ reduction reaction (CO₂RR) catalysts. For developing high-performance CO₂RR catalysts, herein we report a 0D/2D heterojunction structure of SnO₂ nanodots (∼2 nm) confined on graphitic carbon nitride (g-C₃N₄) nanosheets for promoting the conversion of CO₂ to formate. Experimental and theoretical studies demonstrate that the abundant N-coordinating sites of g-C₃N₄ and highly distributed SnO₂ nanodots synergistically lead to strong metal oxide-support interactions, and the substantial heterojunction interface in SnO₂/g-C₃N₄ has induced efficient electron transfer from electron-rich g-C₃N₄ to SnO₂ mainly through p-p orbital couplings. As a result, the SnO₂/g-C₃N₄ heterojunction provides superior activity and stability for the conversion of CO₂RR to formate, with a Faradic efficiency of 91.7% at −0.88 V vs RHE. Moreover, the proposed 0D/2D heterojunction strategy was extended to In₂O₃/g-C₃N₄, supplying a universal strategy to achieve efficient hybrid catalysts for CO₂RR in the production of high-value chemicals.