Qin Jiangzhou, Zhao Wenjun, Hu Xia, Li Jiang, Ndokoye Pancras, Liu Baojun
College of Resource and Environmental Engineering, Guizhou University, Guiyang 550025, China.
Guizhou Karst Environmental Ecosystems Observation and Research Station, Ministry of Education, Guiyang 550025, China.
ACS Appl Mater Interfaces. 2021 Feb 17;13(6):7127-7134. doi: 10.1021/acsami.0c19282. Epub 2021 Feb 8.
Solar-driven conversion of nitrogen (N) to ammonia (NH) is highly appealing, yet in its infancy, the low photocatalytic efficiency and unclear adsorption and activation mechanisms of N are still issues to be addressed. In this study, ultrathin alloyed MoWS nanosheets with tunable hexagonal (2H)/trigonal (1T) phase ratios were proposed to boost photoreduction N efficiency, while the mechanisms of N adsorption and activation were explored simultaneously. The alloyed MoWS nanosheets for the 1T phase concentration of 33.6% and Mo/W = 0.68:0.32 were proven to reach about 111 μmol g h under visible light, which is 3.7 (or 3)-fold higher than that of pristine MoS (or WS). With the aid of density functional theory calculations and N adsorption X-ray absorption near-edge fine structure techniques, the adsorption and activation behaviors of N over the interface of MoWS nanosheets were investigated during the N reduction process. The results show that the W doping causes a higher electron density state in W 5d orbitals, which can further polarize the adsorbed N molecules for adsorption and activation. This work provides a new insight into the adsorption and activation mechanisms for the NH synthesis.
太阳能驱动的氮（N）向氨（NH₃）的转化极具吸引力，但仍处于起步阶段，光催化效率低以及氮的吸附和活化机制不明仍是有待解决的问题。在本研究中，提出了具有可调六方（2H）/三角（1T）相比例的超薄合金化MoWS纳米片以提高光还原氮的效率，同时探索氮的吸附和活化机制。结果表明，1T相浓度为33.6%且Mo/W = 0.68:0.32的合金化MoWS纳米片在可见光下的产氨速率约为111 μmol g⁻¹ h⁻¹，比原始MoS₂（或WS₂）高3.7（或3）倍。借助密度泛函理论计算和氮吸附X射线吸收近边精细结构技术，研究了氮还原过程中氮在MoWS纳米片界面上的吸附和活化行为。结果表明，W掺杂导致W 5d轨道具有更高的电子密度状态，这可以进一步极化吸附的氮分子以进行吸附和活化。这项工作为氨合成的吸附和活化机制提供了新的见解。
