Luo Wuqing, Li An, Yang Baopeng, Pang Hong, Fu Junwei, Chen Gen, Liu Min, Liu Xiaohe, Ma Renzhi, Ye Jinhua, Zhang Ning
School of Materials Science and Engineering, Central South University, Changsha 410083, Hunan, P. R. China.
School of Physical Science and Electronics, Central South University, Changsha 410083, Hunan, P. R. China.
ACS Appl Mater Interfaces. 2023 Mar 29;15(12):15387-15395. doi: 10.1021/acsami.2c21966. Epub 2023 Mar 16.
ZnS materials exhibit very negative potential of the conduction band, which is promising in photocatalytic reduction reactions. Unfortunately, previously reported ZnS materials for photocatalysis are mainly in the cubic phase, which produce high activity for H evolutions and low activity toward CO reductions. Herein, a hexagonal phase ZnS photocatalyst is fabricated for highly efficient CO reduction reactions. The hexagonal ZnS nanoplates with the pure phase and well crystallization are synthesized via three-step solvothermal methods. In photocatalytic CO reduction reactions under an aqueous solution environment, the hexagonal ZnS produces a CO selectivity of 21%, which is distinctly higher than that of 0.2% for commonly used cubic ZnS. The energy band study suggests that hexagonal ZnS possesses a slightly more negative conduction band and wider bandgap than cubic ZnS. Theoretical calculations reveal that the hexagonal ZnS possesses increased electron density around Zn atoms as that of cubic ZnS. Furthermore, hexagonal ZnS exhibits relatively reduced absorption energy of CO reduction intermediates and increased absorption energy of H* as cubic ZnS, which result in better selectivity toward CO reduction reactions. This study offers deep insights into the synthesis and electronic structure of hexagonal ZnS for CO reduction reactions, which inspire the design of highly active photocatalysts for artificial photosynthesis.
硫化锌材料具有非常负的导带电位，这在光催化还原反应中很有前景。不幸的是，先前报道的用于光催化的硫化锌材料主要是立方相，其对析氢反应具有高活性，而对一氧化碳还原反应的活性较低。在此，制备了一种六方相硫化锌光催化剂用于高效的一氧化碳还原反应。通过三步溶剂热法合成了具有纯相和良好结晶性的六方相硫化锌纳米片。在水溶液环境下的光催化一氧化碳还原反应中，六方相硫化锌产生的一氧化碳选择性为21%，明显高于常用立方相硫化锌的0.2%。能带研究表明，六方相硫化锌的导带电位比立方相硫化锌略负，且带隙更宽。理论计算表明，六方相硫化锌中锌原子周围的电子密度与立方相硫化锌相比有所增加。此外，与立方相硫化锌相比，六方相硫化锌对一氧化碳还原中间体的吸收能量相对降低，而对H*的吸收能量增加，这导致其对一氧化碳还原反应具有更好的选择性。这项研究为用于一氧化碳还原反应的六方相硫化锌的合成和电子结构提供了深入的见解，这激发了用于人工光合作用的高活性光催化剂的设计。
