Yin Guowei, Zhang Chunxiao, Liu Yundan, Sun Yuping, Qi Xiang
School of Physics and Optoelectronic Engineering, Shandong University of Technology, Zibo 255000, China.
Hunan Key Laboratory of Micro-Nano Energy Materials and Devices, Xiangtan University, Xiangtan 411105, China.
Nanomaterials (Basel). 2024 Jul 11;14(14):1183. doi: 10.3390/nano14141183.
Transition metal (TM) single-atom catalysts (SACs) have been widely applied in photocatalytic CO reduction. In this work, - codoping engineering is introduced to account for the modulation of photocatalytic CO reduction on a two-dimensional (2D) bismuth-oxyhalide-based cathode by using first-principles calculation. - codoping is established via the Coulomb interactions between the negatively charged TM SACs and the positively charged vacancy () in the dopant-defect pairs. Based on the formation energy of charged defects, neutral dopant-defect pairs for the Fe, Co, and Ni SACs () and the -1 charge state of the Cu SAC-based pair () are stable. The electrostatic attraction of the - codoping strengthens the stability and solubility of TM SACs by neutralizing the oppositely charged defect and TM dopant. The - codoping stabilizes the electron accumulation around the TM SACs. Accumulated electrons modify the -orbital alignment and shift the -band center toward the Fermi level, enhancing the reducing capacity of TM SACs based on the d-band theory. Besides the electrostatic attraction of the - codoping, the also accumulates additional electrons surrounding Cu SACs and forms a half-occupied state, which further upshifts the -band center and improves photocatalytic CO reduction. The metastability of multivacancies limits the concentration of the - pairs with multivacancies ( (n > 1)). Positively charged centers around the (n > 1) hinders the CO reduction by shielding the charge transfer to the CO molecule.
过渡金属（TM）单原子催化剂（SACs）已广泛应用于光催化CO还原。在这项工作中，通过第一性原理计算引入了-共掺杂工程，以解释二维（2D）卤氧化铋基阴极上光催化CO还原的调制。-共掺杂是通过带负电的TM SACs与掺杂剂-缺陷对中带正电的空位（）之间的库仑相互作用建立的。基于带电缺陷的形成能，Fe、Co和Ni SACs（）的中性掺杂剂-缺陷对以及基于Cu SAC的对（）的-1电荷态是稳定的。-共掺杂的静电吸引力通过中和带相反电荷的缺陷和TM掺杂剂来增强TM SACs的稳定性和溶解性。-共掺杂使TM SACs周围的电子积累稳定。积累的电子改变了-轨道排列并将-带中心向费米能级移动，基于d带理论增强了TM SACs的还原能力。除了-共掺杂的静电吸引力外，还在Cu SACs周围积累了额外的电子并形成了半占据的状态，这进一步使-带中心上移并改善了光催化CO还原。多空位的亚稳性限制了具有多空位（（n>1））的-对的浓度。（n>1）周围的带正电中心通过屏蔽向CO分子的电荷转移来阻碍CO还原。
