Molecularly Engineered Strong Metal Oxide–Support Interaction Enables Highly Efficient and Stable CO2 Electroreduction

Strong metal–support interaction (SMSI), commonly happening between metal and metal oxide support, has drawn significant attention in heterogeneous catalysis due to its capability of enhancing the activity and stability of catalysts. Herein, the strong interaction between metal oxide and carbon supports is discovered to significantly boost the performance for electrocatalytic CO2 reduction reaction (CO2RR). A molecular engineering strategy is designed to develop undoped, N-doped, S-doped, and N,S-codoped porous carbon supports with similar physical properties (denoted as C, NC, SC, and NSC, respectively). These supports can host high-density SnO2 nanoparticles (over 60 wt. %) in a small size of ∼3.5 nm and good distribution, providing an excellent platform to understand the strong metal oxide–support interaction (SMOSI) and their influence on electrocatalytic performance. Systematic experimental and theoretical investigations discover the SMOSI between SnO2 nanoparticles and carbon supports in an order of SnO2/NSC > SnO2/NC > SnO2/SC > SnO2/C. Such SMOSI enables the effective electron transfer from carbon support to SnO2 nanoparticles, strengthening the adsorption of key reaction intermediate of CO2•– and thus promoting CO2RR. With the strongest SMOSI, SnO2/NSC exhibits significantly enhanced selectivity and activity for CO2 reduction to HCOOH with a high faradaic efficiency of 94.4% and an extraordinary partial current density of 56.0 mA·cm–2 in an H-cell, outperforming the majority of Sn-based catalysts. Notably, SMOSI can simultaneously secure the active sites and thus remarkably enhance their catalytic durability, making it a promising strategy for exploring efficient and stable catalysts for diverse applications.