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

To investigate synergistic effect between geometric and electronic structures on directing CO ₂ RR 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 Bi ³⁺ dopant can be rationalized by the regulation of [*COOH]/[*CO] adsorption capacities through the appropriate doping of Bi ³⁺ 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─Bi ³⁺ ]) enabled by Cu ₁ Bi ³⁺ ₂ motif in single-phase Cu ₁₅₀ Bi ₁ nanocatalyst drives CO2-to-CO conversion. In contrast, the study of dynamic Bi speciation and phase transformation in dual-phase Cu ₅₀ Bi ₁ nanocatalyst unveils that the Bi ⁰ -Bi ⁰ contribution emerges at the expense of BOC phase, suggesting metallic Bi ⁰ phase acting as [H] ^˙ formation center switches CO ₂ RR 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 CO ₂ reduction through the distinct surface-bound intermediates and presents molecular-level understanding of catalytic mechanism for CO/HCOO ⁻ formation.