In-built Tb4+/Tb3+ redox centers in terbium-doped bismuth molybdate nanograss for enhanced photocatalytic activity

Abstract

A series of terbium-doped Bi₂MoO₆ with different Tb contents were synthesized using a hydrothermal method. The crystalline structure, surface area, morphology, chemical state and optical properties were analyzed in detail. The photocatalytic activity of the samples was evaluated by degradation of organics under visible light irradiation. The results indicated that doping of terbium ions could obviously improve the photocatalytic activity of Bi₂MoO₆, which was attributed to the generation of Tb⁴⁺/Tb³⁺ redox centers in terbium-doped Bi₂MoO₆. The photoluminescence (PL) spectroscopy, photocurrent measurement and active species trapping experiments suggest that the recombination of photo-generated electron–hole pairs was efficiently restrained by a trapping–releasing process between the Tb⁴⁺ and Tb³⁺ ions.