Unveiled the Structure‐Selectivity Relationship for Carbon Dioxide Reduction Triggered by Bi‐Doped Cu‐Based Nanocatalysts

Abstract To investigate synergistic effect between geometric and electronic structures on directing CO₂RR selectivity, water phase synthetic protocol and surface architecture engineering strategy are developed to construct monodispersed Bi‐doped Cu‐based nanocatalysts. The strongly correlated catalytic directionality and Bi³⁺ dopant can be rationalized by the regulation of [*COOH]/[*CO] adsorption capacities through the appropriate doping of Bi³⁺ electronic modulator, resulting in volcano relationship between FE_CO/TOF_CO and surface EVBM values. Spectroscopic study reveals that the dual‐site binding mode ([Cu─μ─C(═O)O─Bi³⁺]) enabled by Cu₁Bi³⁺₂ motif in single‐phase Cu₁₅₀Bi₁ nanocatalyst drives CO2‐to‐CO conversion. In contrast, the study of dynamic Bi speciation and phase transformation in dual‐phase Cu₅₀Bi₁ nanocatalyst unveils that the Bi⁰‐Bi⁰ contribution emerges at the expense of BOC phase, suggesting metallic Bi⁰ phase acting as [H]^˙ formation center switches CO₂RR selectivity toward CO2‐to‐HCOO⁻ conversion via [*OCHO] and [*OCHOK] intermediates. This work provides significant insight into how geometric architecture cooperates with electronic effect and catalytic motif/phase to guide the selectivity of electrocatalytic CO₂ reduction through the distinct surface‐bound intermediates and presents molecular‐level understanding of catalytic mechanism for CO/HCOO⁻ formation.