Low-cost dual cocatalysts BiVO4 for highly efficient visible photocatalytic oxidation

Abstract

The cocatalysts of noble metals are reported to play a significant role in improving the photocatalytic activity in water splitting and pollutant degradation reactions. The high price of noble metals limits their further application in industry. Herein, for the first time, we report that thiophene, rhodamine B (RhB) and methyl orange (MO) can be efficiently oxidized on BiVO₄ co-loaded with Ni and CuO cocatalysts (denoted as Ni–CuO/BiVO₄) under visible light irradiation with molecular oxygen as the oxidant. Moreover, 0.05 wt% Ni–0.5 wt% CuO/BiVO₄ possesses high photocatalytic activity (over 94% conversion of thiophene), which is close to Pt–RuO₂/BiVO₄ (99% conversion of thiophene). XPS and ESR measurements showed that the activation of molecular oxygen and oxidation of pollutant molecules simultaneously take place on BiVO₄ co-loaded with Ni/Cu and CuO/Cu₂O cocatalysts. The considerable enhancement of photocatalytic activity can be attributed to the simultaneous presence of the reduction cocatalyst Ni/Cu and oxidation cocatalyst CuO/Cu₂O, which are beneficial for the efficient separation and transfer of the photo-generated electrons and holes. Such visible-light-responsive semiconductor loaded with earth-abundant dual cocatalysts has great potential in both solar energy conversion and further industrial applications.