Morphology control of highly efficient visible-light driven carbon-doped POM photocatalysts

Abstract

Polyoxometallates (POMs) have been extensively adopted as photocatalysts due to the high redox capacity, strong acidity and high thermal stability. However, the water solubility and narrow light absorption in UV-Vis region restrict further application. Towards the above challenges, carbon-doped POMs with different morphologies were successfully prepared via the thermal treatment of urea phosphotungstate and thiourea phosphotungstate in this work. Through carbon doping, the absorption range of POM photocatalysts has been extended to the visible region by introducing mid gap states. The carbon-doped POM photocatalysts exhibit good visible-light photocatalytic activity. The photocatalytic degradation efficiency of imidacloprid with the carbon-doped POM photocatalysts reaches 76.30% with a rate constant of 0.34 h−1. The main reactive species involved in the reaction of imidacloprid photocatalytic degradation are h+ and O2−. The C-doped POM photocatalysts are water insoluble and can be reused with showing a photocatalytic degradation efficiency of 69.59% after 3 times of repetition. This work provides a promising strategy for doping POM photocatalysts.