Dual‐Site Activation for Efficient Acidic CO ₂ Electroreduction at Industrial‐Level Current Densities

Abstract Electroreduction of CO ₂ to formic acid in acidic media offers a promising approach for value‐added CO ₂ utilization. However, achieving high selectivity for formic acid in acidic electrolytes remains challenging due to the competitive hydrogen evolution reaction (HER), particularly at industrially relevant current densities. Herein, a charge redistribution modulation strategy is demonstrated by constructing the CuS /SnS ₂ Mott–Schottky catalyst to enhance formic acid selectivity. Experiments and calculation results reveal the broadening of Sn orbitals and reduced orbital symmetry of Sn orbitals contribute to enhanced CO ₂ adsorption, while the modulated Cu sites with a stronger Lewis acid character stabilize ^* OCHO intermediates more effectively. This enables dual‐site activation for efficient CO ₂ electroreduction into formic acid synthesis. Consequently, the optimized CuS/SnS ₂ catalysts achieve a maximum formic acid Faradaic efficiency (FE) of 99% in acidic electrolytes and maintain selectivity above 80% at a current density of 1 A cm ⁻² , significantly surpassing the performance of CuS and SnS ₂ alone. Moreover, the excellent selectivity across pH‐universal electrolytes demonstrates that dual‐site activation is a promising strategy for designing highly efficient CO ₂ reduction reaction catalysts.