Bi−O Site Lattice Engineering towards Durable and Efficient CO 2 Electroreduction

ABSTRACT Bismuth‐based oxides show promise for the CO 2 reduction reaction due to their Bi−O active sites, but suffer from self‐reduction and deactivation under operating potentials. To address these challenges, a cooperative strategy integrating indium doping with superlattice engineering (In‐doped Bi 2 O 2 CO 3 , IBOC) is employed to enhance both activity and durability. By integrating multi‐dimensional in situ characterization with theoretical simulations, this study provides direct and complementary evidence clarifying the origin of stabilization, thereby establishing a holistic link between lattice engineering and catalytic behavior. Indium incorporation induces lattice distortion and asymmetric coordination to form Bi─O─In bonds, while the implemented superlattice engineering enables reversible CO 3 2− intercalation. These synergistic interactions strengthen the Bi─O framework, buffer local pH, and suppress over‐reduction, thereby preserving active motifs and selectively tuning the adsorption of key intermediates, which accounts for the enhanced formate selectivity and durability. Consequently, the optimized IBOC catalyst with an indium loading of 4 at% (IBOC‐4) demonstrates excellent stability (>1000 h), a remarkable formate partial current density of ∼900 mA cm −2 at −0.9 V without iR compensation, and FE formate >95% @200 mA cm −2 at industrial current densities. This work establishes a generalized paradigm and mechanistic foundation for rationally designing durable and active oxide catalysts for sustainable energy conversions.