Co(2+) substituted for Bi(3+) in BiVO(4) and its enhanced photocatalytic activity under visible LED light irradiation

We investigated the fabrication of Co-doped BiVO(4) (Bi(1−x)Co(x)VO(4+δ), 0.05 < x < 0.5) by the substitution of Co ions for Bi sites in BiVO(4). The X-ray diffraction (XRD), Raman, and X-ray photoelectron spectroscopy (XPS) results indicated that the substitution of Co(2+) ions for Bi(3+) sites in BiVO(4) was successful, although a change in the crystal phase of BiVO(4) did not occur. UV-vis DRS and PL results suggested that the Co-incorporation could slightly improve the visible light absorption of BiVO(4) and induce the separation of photoinduced electron–hole pairs; therefore, a significant enhancement of photocatalytic performance was achieved. The Bi(0.8)Co(0.2)VO(4+δ) 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.