Synergetic Surface Modulation of ZnO/Pt@ZIF-8 Hybrid Nanorods for Enhanced Photocatalytic CO2 Valorization

Abstract Artificial photosynthesis, photocatalytic conversion of greenhouse gas CO2 into value-added solar fuels, is a promising strategy for mitigating greenhouse effect and solving energy crisis. ZnO is extensively studied for CO2 valorization, but still generally suffering from retarded charge separation and utilization, and limited CO2 capture and activation. To overcome those disadvantages, novel rod-like core-shell ZnO/Pt@ZIF-8 hybrid photocatalysts with transparent conductive adsorption layers are constructed, with Pt nanoparticles mainly interspersing at the interface of ZnO nanorods and ZIF-8 overlayer. Significantly, the charge potential and dynamics are greatly improved in ZnO/Pt@ZIF-8, owing to the unique synergetic effects of surface passivation effects of ZIF-8 overlayer and Schottky junction effects at ZnO/Pt interface. Moreover, because of the highly porous and transparent features of ZIF-8 overlayer together with the cocatalyst effects of interspersed Pt nanoparticles, the adsorption and activation of CO2 over ZnO/Pt@ZIF-8 can be enhanced simultaneously, without shielding the light harvesting. As a consequence, the photocatalytic CO2 conversion efficiency and selectivity of ZnO/Pt@ZIF-8 hybrid nanorods are significantly enhanced. In particular, the CH3OH evolution rate can be optimized as high as 1.13 μmol g−1 h−1, being 16 and 1.8 times more efficient than the pristine ZnO and binary ZnO/Pt nanorods, respectively. This study will inspire further studies on constructing hybrid photocatalysts with transparent conductive adsorption centers for artificial photosynthesis by synergetic modulation of surface functionalities and integrative regulation of key photocatalytic processes.