Hydroxyl reduced silver nanoparticles on ultrathin boron imidazolate framework nanosheets for electrocatalytic CO2 reduction

Abstract

Electrocatalytic carbon dioxide reduction reaction (CO₂RR) is a promising strategy to mitigate the greenhouse gas effect. The implementation of such a technique highly depends on efficient electrocatalysts. Here, we report a composite catalyst of Ag@BIF-73NSs, prepared by loading Ag nanoparticles on boron imidazolate framework (BIF) nanosheets (BIF-73NSs) through the hydroxyl functional group of the organic ligand in BIF-73NSs, as an electrocatalyst for electroreduction of CO₂ to CO. In the obtained Ag@BIF-73NSs catalysts, ultrasmall Ag nanoparticles (∼2 nm) were evenly dispersed on the ultrathin 2D BIF-73 nanosheets with a thickness of ∼2 nm. Electrocatalytic results clearly demonstrated that Ag@BIF-73NSs exhibits much higher performance for electrocatalytic reduction of CO₂ to CO with a FE close to 90%, which is comparable to those of pure Ag, but comparatively at much lower Ag loading (Ag, 3.39 wt%). Moreover, the mass current density of Ag@BIF-73NSs (1816.67 A cm⁻² g⁻¹ Ag, ICP-AES 3.39 wt% Ag) is 1101-fold higher than that of Ag@graphene (1.65 A cm⁻² g⁻¹ Ag, ICP-AES 57.13 wt% Ag) sheet composites. These results indicate that Ag@BIF-73NSs achieves highly selective CO generation with low metal Ag loading in electrochemical CO₂RR catalysis by evenly loading Ag nanoparticles on ultrathin boron imidazolate framework nanosheets through coordination effects.