Intrinsic Photocatalysis of Morphology and Oxygen Vacancy-Tunable Ultrathin WO3 Nanosheets

Abstract

The oxygen-deficient WO3 nanosheets (WO3 NS) with pore structure were synthesized by a facile solvothermal approach and their microstructure and oxygen vacancy (Vo) were regulated via heat treating atmosphere. The mean thickness of WO3 NS is about 1.2 nm, which is equivalent to the thickness of single atom or molecule layer. The quantitative analyses on the ultrathin WO3 NS of catalytic dynamic and Vo concentrations have been done. The appropriate Vo concentration can play a critical role in the transfer/separation of surface photogenerated carriers. Using phenol as the target compound and hydrogen peroxide as the accelerant, under visible-light irradiation, the apparent rate constant of WO3-Ar NS is about 2.0 times and 1.8 times than that of WO3 nanoparticles and WO3-air NS, respectively. These unique photocatalytic properties were attributed to the contribution of atomic layers, suitable crystal phase and porous surface and appropriate Vo content, which increases the specific surface areas and regulates the electrical properties.