The construction of Yb/Er/Pr triple-doped Bi2WO6 superior photocatalyst and the regulation of superoxide and hydroxyl radicals

Superoxide anions (center dot O-2(-)) and hydroxyl radicals (center dot OH) are vital reactive oxide species (ROS) in the photocatalytic process. In this study, a novel triple-doped bismuth tungstate (Yb/Er/Pr-Bi2WO6) superior photocatalyst was constructed using hydrothermal method. The yield of center dot O-2(-) and center dot OH are concurrently boosted by the synergistic effect for Yb/Er/Pr triple-doping. The X-ray photo-electron spectra confirmed the existence of oxygen vacancy and Pr4+/Pr3+ redox center, which can act as trap electron center to produce more center dot O-2(-) and promote electronholes pairs separation. Meanwhile, Yb and Er doping observably regulated the valence band position of Bi2WO6 from 2.39 V to 2.63 V, which is beneficial to produce more center dot OH. Comprehensive characterization illustrate that Yb/Er/Pr-Bi2WO6 shows superior performance in photocatalytic activity, photocarrier separation and light absorption efficiency compared with the pristine Bi2WO6, single-doped Bi2WO6 and co-doped Bi2WO6. The research provides a simple and valid method for enhancing the visible-light-responding photocatalytic property and exploring the possible enhanced photocatalytic performance mechanism.