ZnO Porous Nanosheets with Partial Surface Modification for Enhanced Charges Separation and High Photocatalytic Activity Under Solar Irradiation

Abstract

ZnO porous nanosheets (PNSs) with partial surface modification were fabricated by means of depositing amorphous BiVO4 on basic zinc carbonate nanosheets followed by calcining at 500 °C. At low levels of anchored amorphous BiVO4, the surface of ZnO PNSs was partially evolved into Bi3.9Zn0.4V1.7O10.5 (BZVO). The measurements for photocurrent and photoluminescence demonstrate that partial-surface BZVO-modified ZnO PNSs (ZB_0.01) could significantly inhibit the recombination of photoinduced carriers. This should be ascribable to the driving from surface potential difference produced by non-junction part and vertical p-n BZVO/ZnO junction part on the surface of ZB_0.01. Furthermore, the photocatalytic efficiency in degradation of reactive brilliant red for ZB_0.01 under weak solar irradiation is about 8 times higher than that under strong visible-light illumination. The discussion regarding reasons for this enhancement demonstrates that each component in photocatalysts having rational valence-band maximum and conduction-band minimum energy levels is essential to obtain high-activity sunlight-driven catalysts.