Oxygen vacancies induced self-assembling synthesis of V4+-BiVO4/rGO core-shell nanorods with enhanced water splitting efficiency and superior sewage purification capability

Abstract

Graphene sheets fully wrapped core-shell structured nanocomposites are receiving increasingly more attention in photocatalysis owing to their amazing charge carriers transporting characteristics. However, the preparation of this interesting and valuable architecture remains a big challenge. Herein, we successfully prepared high-quality V4+-BiVO4/rGO core-shell structured composite nanorods using a facile solution-processed method. Positively charged oxygen vacancies on V4+ self-doped BiVO4 nanorods play a key role in rGO wrapping because they can strongly attract and finally anchor COO anions on them, which finally enables the self-assembling formation of V4+-BVO/rGO core-shell nanocomposite. The optimal photocatalytic O2 evolution rate can reach up to 119.5umolh−1 after wrapping rGO, which is 1.36 times higher than that of bare V4+-BiVO4. Significantly, when treating natural waste water from Huangpu River, 2wt.% V4+-BiVO4/rGO is capable of eliminating 92.6% of TOC and 84.6% of TN under visible light irradiation within 8h indicating its huge practical value. The enhanced photoactivities of V4+-BiVO4/rGO are primarily owing to the fact that rGO shell around the composite nanorods can provide a fast channel for photogenerated electrons migrating and subsequently facilitate e−/h+ separation efficiency. This work provides deep insights into the forming mechanism and properties of high-quality V4+-BiVO4/rGO core-shell structure, and will facilitate the design of other rGO fully wrapped nanocomposites.