Synthesis of novel ternary heterogeneous anatase-TiO2 (B) biphase nanowires/Bi4O5I2 composite photocatalysts for the highly efficient degradation of acetaminophen under visible light irradiation

Bi₄O₅I₂ loaded anatase-TiO₂ (B) biphase nanowires composite photocatalysts were fabricated by an in situ calcination method and exhibited outstanding photocatalytic activity. The microstructure, optical performance and band structure of the composite photocatalysts were investigated by relevant characterizations. The results demonstrated the successful formation of heterojunction between anatase-TiO₂ (B) biphase nanowires and Bi₄O₅I₂, which integrated the advantages of homojunction and heterojunction. Therefore, it definitely improved separation efficiency of photo-induced electron-holes because of the formation of multi-junctions. In order to test the enhanced photocatalytic activity, acetaminophen was chosen as target pollutant. The sample with 67% Bi₄O₅I₂ (TiO₂-Bi₄O₅I₂-3) presented the highest photocatalytic activity on the degradation of acetaminophen and its reaction apparent rate constant was 10 and 25 times as that of Bi₄O₅I₂ and TiO₂ biphase nanowires, respectively. Through trapping experiments and LC-MS/MS analysis, OH was proved to be the key active specie during the photocatalytic process of acetaminophen degradation. Meanwhile a possible degradation pathway was proposed based on the detected intermediate products.

Assembly of Ultra-Thin NiO Layer Over Zn1-x Cdx S for Stable Visible-Light Photocatalytic Overall Water Splitting

Photocatalytic splitting of water into hydrogen and oxygen by using visible light is considered to be a clean, green, and renewable route for solar energy conversion and storage. Although the Zn_1-x Cd_x S catalysts show comparatively higher activity for photocatalytic hydrogen generation under visible-light irradiation, they suffer from serious photocorrosion during the photocatalytic reaction. The deposition of a protective layer over the Zn_1-x Cd_x S catalysts is believed to be an effective way to inhibit photocorrosion. However, only a few materials exhibit satisfactory catalytic properties for hydrogen evolution as well as a good protection ability. In this work, a new Zn_1-x Cd_x S photocatalyst was developed for water splitting under visible-light illumination by assembling an ultrathin NiO layer over Zn_0.8 Cd_0.2 S through an in situ photodeposition method. The as-prepared NiO/Zn_0.8 Cd_0.2 S showed significantly higher activity for overall water splitting compared with Pt/Zn_0.8 Cd_0.2 S under the same conditions without photocorrosion. An apparent quantum efficiency of 0.66 % was achieved for hydrogen evolution at 430 nm with an accomplished multicycle stability for up to 12 h without any significant decay. The strong electronic coupling between the NiO layer and Zn_1-x Cd_x S also promoted efficient charge separation and migration.