Co2+ substituted for Bi3+ in BiVO4 and its enhanced photocatalytic activity under visible LED light irradiation

We investigated the fabrication of Co-doped BiVO4 (Bi1-xCoxVO4+delta, 0.05 < x < 0.5) by the substitution of Co ions for Bi sites in BiVO4. The X-ray diffraction (XRD), Raman, and X-ray photoelectron spectroscopy (XPS) results indicated that the substitution of Co2+ ions for Bi3+ sites in BiVO4 was successful, although a change in the crystal phase of BiVO4 did not occur. UV-vis DRS and PL results suggested that the Co-incorporation could slightly improve the visible light absorption of BiVO4 and induce the separation of photoinduced electron-hole pairs; therefore, a significant enhancement of photocatalytic performance was achieved. The Bi0.8Co0.2VO4+delta sample showed superior photocatalytic activity in comparison with other samples, achieving 96.78% methylene blue (MB) removal within 180 min. In addition, the proposed mechanism of improved photocatalytic activities and the stability of the catalyst were also investigated.