Metal active sites regulation in copper phthalocyanine/bismuth vanadate Z-scheme heterojunction by electron-withdrawing substituent for selective CO2 photoreduction in pure water

Here, a Z-scheme heterojunction photocatalyst by integration of copper phthalocyanine with carboxyl grafting (CuTcPc) and BiVO4 nanosheets (BVO) via the hydroxyl induced assembly strategy has been developed for selective CO2 photoreduction. The optimal CuTcPc/BVO catalyst delivers a 21-fold increments in CO yields compared with pristine BVO and 91 % selectivity towards CO2 reduction, coupled with nearly stoichiometric O2 in pure water. As unraveled by experimental results and theoretical simulations, the remarkably improved photoactivity is attributed to the complementary light absorption of BVO and CuTcPc, the enhanced charge transfer and separation due to the formation of Z-scheme heterojunction and most importantly the preferable CO2 adsorption and activation brought by the adjusted local coordination and electronic environment of central Cu-N4 sites by electron-withdrawing substituents. This study provides a feasible avenue to manipulate the active sites from the perspective of functional substitute tailoring on metal phthalocyanine over novel BiVO4-based Z-scheme heterojunctions for artificial photosynthesis.