Crystal phase engineering Zn0.8Cd0.2S nanocrystals with twin-induced homojunctions for photocatalytic nitrogen fixation under visible light

• Published in: Journal of photochemistry and photobiology. A, Chemistry. Chemistry., 2020-10, Vol.401, p.112766, Article 112766
• Main Authors: Dong, Wanyue, Liu, Yutang, Zeng, Guangming, Cai, Tao, Shao, Luhua, Chen, Hui, Zeng, Wengao, Xia, Xinnian
• Format: Article
• Language: English
• Subjects: Homojunction; Nitrogen fixation; Photocatalysis; Twinned Zn0.8Cd0.2S
• ISSN: 1010-6030; 1873-2666
• DOI: 10.1016/j.jphotochem.2020.112766

[Display omitted] •N2 photofixation on twinning Zn0.8Cd0.2S solid solution nanocrystals (NCs) was innovately reported.•Homojunctions between zinc blend (ZB) and wurtzite (WZ) phases within twinning Zn0.8Cd0.2S NCs can enhance electron-hole pairs separation and steered their transport pathway.•Sufficient electrons were provided for N2 photofixation reaction, which was mainly on (111) crystal facets of ZB segment. Newly developed photocatalysts usually focus on structuring active sites, for enhancing chemical adsorption and reducing activation energy barrier in photocatalysis nitrogen fixation. However, lots of photocatalysts suffer from electron-hole pairs’ recombination in the bulk or on the surface during transportation. Herein, twinned Zn0.8Cd0.2S nanocrystals were successfully applied to photocatalytic nitrogen fixation, affording an ammonia production rate of 66.91 μmol g−1 h−1 under visible light with an AQE of 3.77 % at 420 nm, which were 17-fold and 3-fold higher than the activities of CdS and ZnS, respectively. The inner homojunction enhanced carriers’ transportation, and improved electrons density on zinc blend segment, which could facilitate adsorption of nitrogen and ·H gaining, finally, the nitrogen activation and reduction proceeded through the six electrons reduction process on (111) facets. These results confirm that twinned Zn0.8Cd0.2S nanocrystal is a kind of promising new photocatalyst for solar-driven nitrogen reduction to ammonia.