Influence of cobalt substitution on the crystal structure, band edges and photocatalytic property of hierarchical Bi2WO6 microsphere
An efficient Co2+ substituted Bi2WO6 photocatalyst was synthesized through facile hydrothermal route and the materials were well characterized by P-XRD, FT-IR, FE-SEM, XPS, DRS, BET and PL techniques. The obtained Co2+ substituted Bi2WO6 materials achieved a high photocatalytic activity for Organic dye degradation, 97.5% of dye was photodegraded by 5 mol% of Co2+ substituted Bi2WO6 within 240 min induced by the visible light, which is remarkably better than that of bare and different concentration (1, 3, 7 and 9%) Co2+ substituted Bi2WO6. From the structural, optical and elemental characterization, it has been stated that the substitution of Co2+ ions in the Bi2WO6 lattice to replace W6+ ion sites without substantial changes in the crystal structure. The substituent of Co2+ ions Bi2WO6 played as a strategic role, which narrowed the band gap, leading to an enlargement in visible light absorption ability and suppressing the recombination of photogenerated electron-hole pairs credited to the Co2+ inner energy state. Additionally, a photocatalytic mechanism was interpreted through radical trapping experiments, which disclosed that holes (h+) as a cardinal instigating species for RhB degradation. As well, the stability of the catalyst was performed by recycling experiments, after the four repeating cycles the degradation efficiency was not dramatically reduced. In this study, the results disclose perspective concept that the Co2+ substitution for W6+ may offer an alternative approach to enhance the Bi2WO6 photocatalytic activity.