A BrO3–-modified Bi2O3/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 Bi2O3/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 Bi2O3, the multiple charge transfer channels via the BrO3– 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 H2O oxidation to produce O2 and H2O2. However, the O2 production was small, and the H2O2 yield was about 78.5 μmol g–1 h–1. For CO2 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 Bi2O3. This work provides useful guidance for the design and synthesis of efficient catalysts for photocatalytic N2 fixation.
The regioselective mono-bromination of phenols has been successfully developed with KBr and ZnAl–BrO3−–layered double hydroxides (abbreviated as ZnAl–BrO3−–LDHs) as brominating reagents. The para site is much favorable and the ortho site takes the priority if para site is occupied. This reaction featured with excellent regioselectivity, cheap brominating reagents, mild reaction condition, high atom economy, broad substrate scope, and provided an efficient method to synthesize bromophenols.Keywords:phenol;bromination;regioselecitvity
Although UV and/or VUV tandem I – are often proposed as advanced reduction processes (ARPs) to eliminate micropollutants by generating e aq – , the fate of I – and its byproducts formation remain to be explored. Therefore, this study investigated the iodine species evolution during UV/I – and UV/VUV/I – processes under different influencing factors. Results show that UV/VUV oxidized most of I – to IO 3 – whereas UV only oxidized a portion of I – to intermediate reactive iodine species (RISs, including I 2 , HOI, and I 3 – ); meanwhile, substantial H 2 O 2 was generated only in UV/VUV/I – process but not in UV/I – process, proving that UV/VUV owns stronger oxidation ability than UV alone. Spiking I – into water exerted triple-sided effects by consuming •OH, generating e aq – , and shielding light, thus complicating the systems. Holistically, increasing pH or decreasing dissolved oxygen converted oxidizing environment into reducing condition and caused less RISs formation, especially for UV/VUV/I – . For oxyhalides , neither UV/I – nor UV/VUV/I – degraded ClO 4 – . While UV/I – cannot remove ClO 3 – , UV/VUV/I – reduced ClO 3 – to Cl – . Expectedly, both UV/I – and UV/VUV/I – reduced BrO 3 – to Br – more efficiently than UV and UV/VUV, confirming that I – can enhance the reduction capacities of UV/VUV and UV technologies .
危险品化学品经营许可证（带存储）