Chemically fabricated ZnO/Ag/Ag Mo O /Zn Mo O heterojunction nanophotocatalysts for abating organic dyes in wastewater

Abstract

Semiconductor photocatalytic technology is among the most promising technologies for degrading organic pollutants in wastewater. However, broadening the photocatalytic spectral-response region of the nanomaterial and tuning carrier behavior at heterojunction interfaces remain wastewater-treatment challenges. To address this issue, we fabricated ZnO/Ag/Ag m Mo n O l /Zn x Mo y O z (ZAAZ) heterojunction nanophotocatalysts through a simple one-step chemical reaction between active ZnO nanoparticles and Ag/Ag x H 3− x PMo 12 O 40 (Ag/AgPMo). The as-prepared ZAAZ heterojunction nanophotocatalysts were physically and chemically characterized, photocatalytic activity was evaluated, and the photogenerated carrier-transfer mechanism analyzed. The optimal nanophotocatalyst was highly crystalline and exhibited a bandgap and specific surface area of 3.06 eV and 13.9 m 2 g −1 , respectively; it photodegraded almost 100% of the initial Rhodamine B (RhB) concentration in 90 min under the optimized conditions, which is 3.7-times faster than ZnO nanoparticles. Furthermore, the ZAAZ heterojunction nanophotocatalyst delivered a photocurrent of 8.3 μA cm −2 , which is 31-times higher than that of its ZnO nanoparticle counterpart; it efficiently separated photogenerated carriers, transferred interfacial charges, and degraded 97% of the initial RhB concentration after three cycles of use, highlighting its excellent recyclability . These findings suggest that the developed heterojunction nanophotocatalyst is highly efficient for the photocatalytic degradation of organic water pollutants .