BrO<sub>3</sub><sup>–</sup> Bridge Bi<sub>2</sub>O<sub>3</sub>/Bi(OH)<sub>3</sub> Heterojunction with Multiple Charge Transfer Channels for Efficient Photocatalytic Nitrogen Fixation and CO<sub>2</sub> Reduction
Sitong Liu, Guangmin Ren, Xiangchao Meng
Abstract
A BrO 3 – -modified Bi 2 O 3 /Bi(OH) 3 heterojunction photocatalyst was in situ fabricated by a facile one-pot method and applied in photocatalytic nitrogen fixation. In comparison with Bi(OH) 3, the Bi 2 O 3 /Bi(OH) 3 heterojunction has a larger specific surface area from the nanoflower-like morphology and an extended visible light absorption range. Of special importance, the proper band gap match between Bi(OH) 3 and Bi 2 O 3, the multiple charge transfer channels via the BrO 3 – bridge, and the oriented electron migration in the type-II heterojunction mechanism make a stronger charge separation efficiency. Therefore, the BiO/BiHO-3 sample presented the highest photocatalytic nitrogen reduction performance with an ammonia production rate of 45.28 μmol g –1 h –1, which was 10 times higher than that of Bi(OH) 3 . Photogenerated cavities are consumed during H 2 O oxidation to produce O 2 and H 2 O 2 . However, the O 2 production was small, and the H 2 O 2 yield was about 78.5 μmol g –1 h –1 . For CO 2 reduction, the CO production rate was 52.86 μmol g –1 h –1, which was 1.6 and 1.9 times those of Bi(OH) 3 and Bi 2 O 3 . This work provides useful guidance for the design and synthesis of efficient catalysts for photocatalytic N 2 fixation.