Er3+/Yb3+/Gd3+-triple-modified bismuth molybdate nanosheets photocatalyst with enhanced photocatalytic activity

Abstract

Semiconductor-based heterogeneous photocatalysis is a promising technology for water and air purification without using consumables and generating harmful by-products. Bismuth molybdate as one of the simplest Aurivillius oxides with a narrow band gap of 2.7 eV has got wide attention due to its potential for photocatalytic applications. However, the inherent disadvantages such as a fast recombination of photogenerated electron-hole pairs and slow charge carrier transfer leads to low photocatalytic efficiency. Recently, it was reported that modification with lanthanides ions greatly improves the separation efficiency and migration rate of the interface carrier. Therefore, we report a simple strategy for synthesis Er3+/Yb3+/Gd3+ modified Bi2MoO6 vis hydrothermal method. The photocatalysts were characterized by diffuse reflectance spectroscopy (DRS), photoluminescence spectroscopy (PL) and scanning electron microscopy (SEM). The photocatalytic activity of the powder samples was assessed by the degradation of phenol in the liquid phase under ultraviolet and visible light irradiation. To provide insight into the reactive inviduals participating in the degradation mechanism, a test with scavengers was also performed. The composite photocatalysts exhibit remarkable enhancement of the photocatalytic activity during photocatalytic phenol degradation as compared with bare Bi2MoO6. These excellent photocatalytic performances are ascribed to the synergistic effects of the extended visible light response, and improved separation efficiency of the photoinduced charge carriers.