Photocatalytic enhancement mechanism insight for BiVO4 induced by plasma treatment under different atmospheres

Abstract Introduction of oxygen vacancies on the surface of photocatalyst has been prove to be an impactful channel to boost the photocatalytic activity, which can restrain the recombination of photoactivated carriers and produce defect energy level. Plasma surface treatment can change the stability of the crystal structure, increase the specific surface area of the materials, and produce more oxygen vacancies. In this study, plasma was used to treat BiVO4 under different atmospheres (Ar, N2, H2) to further exalt the photocatalytic capability of BiVO4 with rich oxygen vacancies. X-ray photoelectron spectroscopy and low-temperature electron paramagnetic resonance spectrometer confirmed that oxygen vacancies rich BiVO4 photocatalysts were all successfully fabricated under the different atmospheres. Moreover, Bi0 was in-situ generated on the surface of BiVO4 under H2 atmosphere treatment. Under N2 atmosphere treatment, a new N 2p energy level can be established. Under Ar atmosphere treatment, a new energy level established by oxygen vacancies is formed. The catalytic capability was assessed by decomposition of rhodamine B and tetracycline. Interestingly, after treated under the H2 atmosphere, the degradation ability of Bi0/OVs-BiVO4 for rhodamine B and tetracycline disintegration is 3.1 and 3.3 times of that of the reference BiVO4, respectively. The photocatalytic enhancement mechanism of BiVO4 treated by plasma under different atmospheres was proposed.