New Understanding on Photocatalytic Mechanism of Nitrogen-Doped Graphene Quantum Dots-Decorated BiVO4 Nanojunction Photocatalysts

Hengyan Yang; Ping Wang; Ding Wang; Yuankun Zhu; Kunpeng Xie; Xianglong Zhao; Junhe Yang; Xianying Wang

doi:10.1021/acsomega.7b00603

New Understanding on Photocatalytic Mechanism of Nitrogen-Doped Graphene Quantum Dots-Decorated BiVO₄ Nanojunction Photocatalysts

ACS Omega. 2017 Jul 19;2(7):3766-3773. doi: 10.1021/acsomega.7b00603. eCollection 2017 Jul 31.

Authors

Hengyan Yang¹, Ping Wang¹, Ding Wang¹, Yuankun Zhu¹, Kunpeng Xie², Xianglong Zhao³, Junhe Yang¹, Xianying Wang¹

Affiliations

¹ School of Materials Science and Technology, University of Shanghai for Science and Technology (USST), Jungong Road 516, 200093 Shanghai, P. R. China.
² Chemical Engineering and Competence Centre for Catalysis, Chalmers University of Technology, Chalmersplatsen 4, 41296 Gothenburg, Sweden.
³ Key Laboratory of Materials Physics and Anhui Key Laboratory of Nanomaterials and Nanostructures, Institute of Solid State Physics, Hefei Institutes of Physical Science, Chinese Academy of Sciences, P.O. Box 1125, 230031 Hefei, P. R. China.

Abstract

Bismuth vanadate (BiVO₄) is a promising candidate as a visible-light-driven photocatalyst in the aspect of practical applications. To investigate the origin of active species from BiVO₄ and understand the influence of the variations of the photocatalytic process, comparative studies on zero-dimensional nitrogen-doped graphene quantum dot (NGQD)-decorated BiVO₄ have been carried out for methylene blue photodegradation. It was found that the hydroxyl group-rich NGQD surface and the established heterojunction structure between NGQDs and BiVO₄ were greatly beneficial for the conversion of the ^•OH radical. With NGQD decoration, the dominant oxidant species for NGQDs/BiVO₄ were confirmed to be ^•OH and H₂O₂, rather than holes originating from the valence band of unmodified BiVO₄. The synergistic photocatalytic mechanism with respect to the interfacial charge transport and the conversion of active species was proposed. The achievement of the controllable active species significantly altering the activity may be applied for different photocatalytic reactions.