Photocatalyst based on transition metal-Schiff base ligand and V-doped Kegging-type polyoxometalate for efficient and stable CO2 reduction

Abstract

In order to simultaneously control the greenhouse effect and solve the problem of energy depletion, the strategy of converting CO2 into other energy can be used. In this work, two Keggin-type polyoxometalate-based compounds were synthesized by the hydrothermal method: [(Co(C11H15N7O2)(H2O)2]4{[(Co(C11H15N7O2)(H2O)]2(PWVI11VIVO40)} (PWVI9WV2VIVO40)·14.5H2O (1) and [(Fe(C11H15N7O2)(H2O)2]3{[(Fe(C11H15N7O2)(H2O)]2(BW12O40)}(BW12O40)·11H2O (2). Structural analysis of compound 1 indicate that an interesting V-doped Keggin-type (PWVI11VIVO40)5- anion is succesfully bonded two [(Co(C11H15N7O2)(H2O)]2+ cations to generate a hybrid [(Co(C11H15N7O2)(H2O)]2(PWVI11VIVO40) unit. Through a series of photocatalytic CO2 reduction reaction (CO2RR) experiments, it was found that compound 1 has good photocatalytic performance. The CO generation rate can reach 7081.4 μmol·g-1·h-1 and the selectivity is 83.8%. In addition, the stable and efficient photocatalytic activity of compound 1 was verified after four cycle photocatalytic experiments, which provided a new idea for CO2 photoreduction to CO. While the CO production rates of 103.5 μmol·g-1·h-1 for compound 2. This is because the adsorption energy of CO on Co is lower than Fe. Furthermore, the V-modified of compound 1 enhance CO2 adsorption to promote CO2 conversion.