上海交通大学学报

上海交通大学学报

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锐钛矿TiO2-x(101)表面硝酸根还原路径的第一性原理研究（网络首发）

  

  1. 上海交通大学机械与动力工程学院
  • 基金资助:
    国家自然科学基金（52374391）资助项目

Reaction Pathways of Nitrate Reduction Reaction on (101) Surface of Anatase TiO2 Investigated by First-Principle Calculations

  1. School of Mechanical Engineering, Shanghai Jiao Tong University, 200240 Shanghai, China

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摘要： 为研究硝酸根在锐钛矿TiO2-x(101)表面的还原过程，建立了有无氧空位两种表面模型，采用密度泛函理论对硝酸根在两种表面的还原过程进行理论计算，研究了氧空位对表面电子结构、硝酸根吸附构型和吸附能、还原路径、竞争反应以及产物选择性的影响。结果表明：氧空位改变硝酸根在表面的吸附构型，显著降低其吸附能，并将电位决定步由硝酸根吸附转变为N的氢化过程。此外，氧空位能够大幅提高中间体NO2和NO的脱附能，从而抑制副产物的产生，改善催化剂选择性。尽管氧空位对竞争性析氢反应也有一定的促进作用，但远不及对硝酸根还原反应的促进程度，因此含氧空位的TiO2是电催化硝酸根还原产氨的潜在优异催化剂。

关键词: TiO2, 氧空位, 硝酸根还原, 电催化, 第一性原理计算

Abstract: To understand the nitrate reduction process on the (101) surface of anatase TiO2-x, two surface models with and without oxygen vacancy were established, and density functional theory (DFT) calculations were employed to reveal the effects of oxygen vacancy on the surface electronic structure, adsorption configuration and energy of nitrate, reduction pathway, competitive reaction and product selectivity. The results show that oxygen vacancy changes the adsorption configuration and significantly reduces the adsorption energy of nitrate on the surface, and as a result, shifts the potential determining step (PDS) from nitrate adsorption to the subsequent hydrogenation processes. In addition, oxygen vacancy dramatically increases the desorption energy of the intermediates NO2 and NO, and thus inhibits the formation of by-products and improve the electrocatalytic selectivity. Promotion of the competitive hydrogen evolution reaction (HER) by oxygen vacancy is less pronounced than that of nitrate reduction reaction. Therefore, oxygen deficient TiO2-x is a promising catalyst for electro-catalyzing nitrate reduction to produce ammonia.

Key words: TiO2, oxygen vacancy, nitrate reduction reaction, electrocatalysis, first-principle calculations

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