摘要
本文采用密度泛函理论(DFT)和含时密度泛函理论(TDDFT)方法对多钨酸纳米团簇[XW_(12)O_(40)]^(n-)(X=P,Si,Ge,B)的紫外-可见光谱和电子跃迁机理进行了模拟,并对其光催化劈裂水产氢气机理进行了计算。结果显示,实验观测到紫外-可见吸收峰均来自配体到金属的电荷转移跃迁(LMCT),即电子由氧原子p轨道跃迁到金属钨的d轨道。因单电子还原(OER)中间体激发后总能量超过实验阈值(λ>300nm),催化剂通过能量弛豫回到基态成为有利途径。接下来的双电子还原(TER)和氢气产生均存在热力学有利的放热反应,且质子化在这些过程中扮演了重要角色。多钨酸纳米团簇在整个催化循环中扮演了光敏剂、催化剂、电子给体和受体的角色。
The ultraviolet-visible spectra(UV-Vis),electronic transition mechanism,photo-splitting mechanism of water to obtain H_(2) by polytungstic acid nanoclusters,[XW_(12)O_(40)]^(n-)(X=P,Si,Ge,and B)had been investigated using DFT and TDDFT calculations.The calculation results showed that experimental observed UV-Vis absorption peaks are generated by ligand-to-metal charge transfer transition(LMCT)of the catalysts,that is,the excitation from the p-type orbitals of O-atom to d-type orbitals of W-atom.Since the total energy of one-electron reduction(OER)process exceeds the energy threshold(λ>300 nm),it becomes a favorable pathway for the catalysts to return to the ground state through energy relaxation.The following two-electron reduction(TER)and H;generation both have thermodynamically favorable exothermic reactions,and the protonation plays an important role.The catalysts act as photosensitizer,catalyst,electron reservoir and donner in the entire catalytic cycle.
作者
慈成刚
周霞
覃再鑫
黄茜茜
陈银会
付雪燕
Ci Chenggang;Zhou Xia;Qin Zaixin;Huang Qianqian;Chen Yinhui;Fu Xueyan(Key Laboratory of Computational Catalytic Chemistry of Guizhou Province,Department of Chemistry and Chemical Engineering,Qiannan Normal University for Nationalities,Duyun,558000)
出处
《化学通报》
CAS
CSCD
北大核心
2022年第1期132-138,共7页
Chemistry
基金
贵州省科技厅项目(黔科合基础[2020]1Y050)
黔南民族师范学院项目(qnsyk201601)
大学生创新创业项目(20195201785)资助。
