To overcome the drawback of low photocatalytic efficiency brought by fast electron–hole recombination and narrow photoresponse range, the heterostructured Bi2S3/BiOBr microspheres were designed and synthesized via a facile one-pot solvothermal method. The as-prepared heterostructured Bi2S3/BiOBr photocatalyst exhibits significantly enhanced photoelectrochemical performance and photocatalytic activity for decomposing rhodamine B (RhB) and Brilliant ponceau 5R (BP) compared with pure BiOBr under visible light irradiation, which could be mainly attributed to the formation of a heterojunction in the Bi2S3/BiOBr interface, which can efficiently facilitate the separation of photogenerated electron–hole pairs. Furthermore, a terephthalic acid photoluminescence (TA-PL) probing test and radical trapping experiments demonstrate that the h+ and ·O2− radicals are the dominant reactive species while ·OH radicals could be neglected. In addition, the possible enhanced photocatalytic mechanism is proposed on the basis of the calculated energy band positions and radical trapping experiments.
Hui Li,Fang Deng,Yang Zheng,Li Hua,Chunhua Qu,Xubiao Luo
Fabrication of Z-scheme heterojunctions and crystal facet engineering are effective strategies for enhancing visible-light photocatalytic redox ability. Visible-light-responsive Z-scheme reduced graphene oxide (rGO)/Bi2S3–BiOBr heterojunctions with a tunable exposed BiOBr (102) facet and high stability were prepared by a one-pot solvothermal strategy. A graphene oxide (GO) solution acts as a rGO precursor and crystal facet controlling agent of BiOBr (102). The optimized 1% rGO/Bi2S3–BiOBr catalyst shows a much higher photocatalytic activity in degrading a single-component 2-nitrophenol (2NP) solution and a reducing single-component Cr(VI) solution than Bi2S3, BiOBr and Bi2S3–BiOBr. In the mixture solution of 2NP and Cr(VI), 2NP degradation and Cr(VI) reduction occur simultaneously, and the Cr(VI) reduction efficiency and 2NP degradation efficiency reached 95% and 67%, respectively. The synergism of rGO/Bi2S3–BiOBr for simultaneous 2NP degradation and Cr(VI) reduction can be attributed to the efficient production of electrons and reactive oxygen species. This work sheds light on the design of facet-dependent Z-scheme photocatalysts to advance photocatalytic redox capability.
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