State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084, China.
Key Laboratory for Thermal Science and Power Engineering of the Ministry of Education, Department of Energy and Power Engineering, Tsinghua University, Beijing 100084, China.
Environ Sci Technol. 2021 Jul 6;55(13):9285-9292. doi: 10.1021/acs.est.1c01749. Epub 2021 Jun 15.
Here, we investigate competitive adsorption and photocatalytic reaction over TiO@SiO: NO conversion efficiency decreases by 29.1%, and the adsorption capacity decreases from 0.125 to 0.095 mmol/g due to the influence of SO. According to identification and comparative analysis of the IR signal, SO has little effect on the NO conversion route and intermediates (adsorbed NO → nitrite → nitrate), but accelerates the deactivation of catalysts. The electronic interaction scheme from density functional theory (DFT) confirms that surface hydroxyls create an unsaturated coordination of neighboring Ti or O atoms, which is favorable for NO/SO adsorption on anatase (101). In addition, the lone pair electrons of N or S atoms prefer to be delocalized and form covalent bonds with active surface-O on the (101) facet with terminal hydroxyls. However, preadsorbed SO could offset the increase of hydroxyls and strongly inhibit NO adsorption, which is consistent with the result performance evaluation. A possible reaction mechanism characterized by oxygen vacancies and·O is proposed, while the essential reason of catalyst deactivation and regeneration is theoretically analyzed based on the experimental and DFT calculation.
在这里，我们研究了 TiO@SiO2 上的竞争吸附和光催化反应：由于 SO2 的影响，NO 的转化率降低了 29.1%，吸附容量从 0.125mmol/g 降低到 0.095mmol/g。根据 IR 信号的鉴定和对比分析，SO2 对 NO 转化途径和中间体（吸附的 NO→亚硝酸盐→硝酸盐）影响不大，但会加速催化剂失活。从密度泛函理论（DFT）的电子相互作用方案证实，表面羟基在锐钛矿（101）上为相邻的 Ti 或 O 原子创造了不饱和配位，有利于 NO/SO2 的吸附。此外，N 或 S 原子的孤对电子更倾向于离域，并与末端羟基的（101）面上的活性表面-O 形成共价键。然而，预吸附的 SO2 可以抵消羟基的增加，并强烈抑制 NO 的吸附，这与性能评估的结果一致。提出了一种以氧空位和·O 为特征的可能反应机理，同时根据实验和 DFT 计算从理论上分析了催化剂失活和再生的根本原因。
