The Bi/Bi2WO6 heterojunction with stable interface contact and enhanced visible-light photocatalytic activity for phenol and Cr(VI) removal

BACKGROUNDSemiconductor photocatalysis is the most promising green and energy-saving technology for environmental remediation. Unfortunately, photocatalysis nanotechnology for its practical application is often challenged by the low capturing ability for visible light and use of expensive noble metals. In this work, we report the non-noble Bi nanoparticles assembled on Bi2WO6 with enhanced visible-light photocatalytic activity for decontamination of phenol and hexavalent chromium in water. RESULTSThe 3% Bi/Bi2WO6 composite had the highest photocatalytic activity compared to pristine Bi2WO6, which could completely decompose phenol into small products within 120min. More importantly, the Cr(VI) removal rate of the 3% Bi/Bi2WO6 catalyst in the presence of triethanolamine (TEOA, 2%) after irradiation for 12min was up to 96.2%. CONCLUSIONSThe improved photocatalytic performance could be due to the fast transfer of photogenerated charge carried by the formation of an anti-barrier layer at the interface between metal Bi nanoparticles and the n-type Bi2WO6 semiconductor; the enhancement of electron energy may be attributed to the localized surface plasmon resonance properties of Bi nanoparticles, as well as conspicuously strengthened and broad light-capturing ability across the whole visible-light range. This strategy could provide some inspiration for the design of other Bi-based semiconductor heterostructures for decomposing harmful organic pollutants in wastewater and purifying hazardous gases in the air. (c) 2018 Society of Chemical Industry