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New Insights on Competitive Adsorption of NO/SO2 on TiO2 Anatase for Photocatalytic NO Oxidation
Environmental Science & Technology ( IF 10.8 ) Pub Date : 2021-06-15 , DOI: 10.1021/acs.est.1c01749
Zhen Chen 1, 2 , Haibo Yin 1 , Chizhong Wang 1 , Rong Wang 2 , Yue Peng 1 , Changfu You 2 , Junhua Li 1
Affiliation  

Here, we investigate competitive adsorption and photocatalytic reaction over TiO2@SiO2: 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 SO2. According to identification and comparative analysis of the IR signal, SO2 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/SO2 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 SO2 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·O2 is proposed, while the essential reason of catalyst deactivation and regeneration is theoretically analyzed based on the experimental and DFT calculation.

中文翻译:

NO/SO 2在 TiO 2锐钛矿上的竞争吸附用于光催化 NO 氧化的新见解

在这里,我们研究了 TiO 2 @SiO 2 上的竞争吸附和光催化反应:由于 SO 2的影响,NO 转化效率降低了 29.1%,吸附容量从 0.125 降低到 0.095 mmol/g 。根据红外信号的鉴定和对比分析,SO 2对NO转化路线和中间体(吸附NO→亚硝酸盐→硝酸盐)影响不大,但会加速催化剂失活。密度泛函理论 (DFT) 的电子相互作用方案证实,表面羟基会产生相邻 Ti 或 O 原子的不饱和配位,这有利于 NO/SO 2在锐钛矿上的吸附 (101)。此外,N 或 S 原子的孤对电子更喜欢离域并与具有末端羟基的(101)面上的活性表面-O 形成共价键。然而,预吸附的 SO 2可以抵消羟基的增加并强烈抑制 NO 吸附,这与结果性能评估一致。提出了以氧空位和·O 2 -为特征的可能反应机理,并基于实验和DFT计算从理论上分析了催化剂失活和再生的根本原因。
更新日期:2021-07-06
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