One-Pot Synthesis of Highly Dispersed VO2 on g-C3N4 Nanomeshes for Advanced Oxidation

Abstract

Advanced oxidation catalyzed by metal oxides is a promising approach for degrading organic pollutants in wastewater. A critical strategy to enhance the performance of these catalysts is optimizing the dispersion of their active components through innovative synthesis methods. In this study, we report a one-pot synthesis of g-C3N4 nanomeshes supported with highly dispersed VO2 catalysts (V-g-C3N4) for the advanced oxidation of methylene blue (MB). The characterization results reveal that the involvement of VCl3 in the pyrolysis of melamine facilitates the formation of g-C3N4 nanomeshes with abundant amino groups (NH/NH2). The strong interaction between vanadia species and amino groups prevents VO2 particles from agglomerating, resulting in a significantly higher vanadia dispersion than V-g-C3N4-im synthesized via the traditional impregnation method. V-g-C3N4 exhibits a sophisticated microstructure and surface structure, which leads to a rate constant 2.3-fold higher than V-g-C3N4-im in the catalytic degradation of methylene blue using H2O2 as the oxidant. X-ray photoelectron spectroscopy, trapping experiments, and electron paramagnetic resonance measurements reveal that the rapid adsorption and fast diffusion of MB over g-C3N4 nanomeshes, together with the efficient H2O2 activation into ·OH radicals via the V4+/V5+ redox cycle, synergistically contribute to the superior MB removal efficiency of V-g-C3N4. Moreover, V-g-C3N4 demonstrates no significant decrease in activity even after the fourth cycle, indicating its excellent stability during the pollutant removal process.