In Situ Synthesis of n-n Bi₂MoO₆&Bi₂S₃Heterojunctions for Highly Efficient Photocatalytic Removal of Cr(VI).

Xiu-Qing Qiao, Zhen-Wei Zhang, Qiu-Hao Li, Dong-Fang Hou, qichun zhang,Jian Zhang,Dong-Sheng Li,Pingyun Fengand Xianhui Bu

Exploiting novel photocatalysts with high efficiency and durability for reduction hexavalent chromium (Cr(VI)) has been the research focus in both fundamental science and industrial applications. In this work, we synthesized a novel two-dimensional (2D) n-n Bi₂MoO₆&Bi₂S₃heterojunctions by a facile in situ anion exchange process for the remarkable removal of Cr(VI). Results show that Bi₂MoO₆&Bi₂S₃heterojunctions with core-shell structure are formed through the intimate contact of Bi₂MoO₆core and Bi₂S₃shell. The as-prepared Bi₂MoO₆&Bi₂S₃heterojunctions exhibit unprecedented photocatalytic activity for reduction of Cr(VI) under visible light irradiation. Among which, the optimized BMO-S1 display the highest reduction efficiency (Κ_app=0.164 min^-1) for Cr(VI) reduction. To the best of our knowledge, it is the highest reduction rate achieved with reported photocatalysts for Cr(VI) reduction under visible-light irradiation. Detailed studies show that the strong selective adsorption for Cr(VI) plays important role for the unprecedented photocatalytic activity. Moreover, the intimate heterounction between Bi₂MoO₆core and Bi₂S₃shell can efficiently deteriorate the charge carrier recombination and the Bi₂S₃boost visible light harvesting also contribute to the amazing photocatalytic catalytic activity, which were proved by the PL, EIS and transient photocurrent response. The characterization of Motte-Schottky and DRS prove the Bi₂MoO₆&Bi₂S₃heterojunctions established a type-II band alignment with intimate contact, accounting for the efficient transfer and separation of photogenerated carriers. This work provides a simple route for the facial synthesis of heterojunction photocatalysts for the Cr(VI) reduction in industrial applications.

文章链接：https://pubs.rsc.org/en/content/articlelanding/2018/ta/c8ta08294d#!divAbstract