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.