Cong Vo Thanh, Van Son Nguyen, Diem Do Quy, Pham Son Quynh Thai
Faculty of Chemical Engineering, Industrial University of Ho Chi Minh City, Ho Chi Minh City, Vietnam.
J Mol Model. 2022 Mar 5;28(4):84. doi: 10.1007/s00894-022-05057-3.
This work has presented a calculated study of the water-gas shift reaction (WGSR) performing on the models of ZnO only and six-atomic copper cluster deposited on the ZnO surfaces (6Cu/ZnO) using density functional theory (DFT). The most stable configurations of ZnO and 6Cu/ZnO surfaces were found and used for the mechanism calculations of WGSR. The carboxyl mechanism of WGSR was proposed to find the reaction pathway. Based on this pathway, WGSR occurred at the elementary reaction of COOH intermediate formation as the rate-controlling step on 6Cu/ZnO surface, and the elementary reaction of H-H association as the rate-controlling step on ZnO surface, in which the highest activation energies were calculated as 1.05 eV and 1.56 eV for 6Cu/ZnO and ZnO surfaces, respectively. These calculations indicated that the 6Cu/ZnO was more favorable and more effective than ZnO as a catalyst for WGSR. In addition, the nature of bonds of CO and HO adsorption on ZnO and 6Cu/ZnO surfaces was also analyzed using the local density of states (LDOS) and electron density difference (EDD) methods.
本研究利用密度泛函理论（DFT），对仅基于氧化锌（ZnO）模型以及沉积在ZnO表面的六原子铜簇（6Cu/ZnO）模型上进行的水煤气变换反应（WGSR）进行了计算研究。找到了ZnO和6Cu/ZnO表面最稳定的构型，并将其用于WGSR的机理计算。提出了WGSR的羧基机理以寻找反应路径。基于该路径，WGSR在6Cu/ZnO表面上以COOH中间体形成的基元反应作为速率控制步骤发生，而在ZnO表面上以H-H缔合的基元反应作为速率控制步骤发生，其中6Cu/ZnO和ZnO表面的最高活化能分别计算为1.05 eV和1.56 eV。这些计算表明，6Cu/ZnO作为WGSR的催化剂比ZnO更有利且更有效。此外，还使用局域态密度（LDOS）和电子密度差（EDD）方法分析了CO和HO在ZnO和6Cu/ZnO表面上的吸附键性质。
