Face‐Dependent Reconstruction of Bi‐Oxyiodides toward Selective Growth of (BiO)2CO3 Edge Side to Maximize CO2 Conversion Efficiency

Abstract

AbstractChemical reconstruction of bismuth oxyiodides using bicarbonates is tried to selectively grow (BiO)2CO3 edge side. Orthorhombic o‐Bi5O7I undergoes a total reconstruction process by its phase transformation into tetragonal (BiO)2CO3 (BOC‐o) to form a well‐aligned nanosheet array with maximally exposing CO32− moiety at the edge side. The post‐reconstruction BOC‐o catalyst achieved 100 % Faradaic efficiency at −0.86 V vs. RHE for CO2‐to‐formate conversion. However, another conservative reconstruction of tetragonal t‐BiOI into tetragonal (BiO)2CO3 (BOC‐t) exposed majorly a less reactive [BiO]+ layer. At low overpotential regions, the catalytic cycle of BOC‐o begins with the initial conversion of the CO32− moiety into formate at the [−OBi−(CO3)−BiO−] site, but at high overpotential regions, the [BiO]+ layer undergoes reduction to metallic Bi and multi‐catalytic species proceed with CO2 reduction. Otherwise, the deactivation of Bi+ site by an organic molecule switched on another catalysis of proton reduction, preventing CO2 reduction.