Constructing a tunable defect structure in TiO2 for photocatalytic nitrogen fixation
Constructing a tunable defect structure in TiO2 for photocatalytic nitrogen fixation
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DOI：
10.1039/c9ta10471b
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发表时间：
2020
影响因子：
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通讯作者：
Guoqiang Zhang;Xun Yang;Chuanxin He;Peixin Zhang;Hongwei Mi
中科院分区：
文献类型：
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作者：
Guoqiang Zhang;Xun Yang;Chuanxin He;Peixin Zhang;Hongwei Mi
能够精确调节氧空位（OV）浓度的光催化系统，这可能有助于阐明OV浓度对N2固定活性的影响，仍然是稀缺的。在这里，我们表明，在TiO 2中的过量的OV，同时增加N2分子的吸附活化能力，表现出令人失望的活动，由于电荷分离效率的降低。在优化OV浓度的情况下，TiO 2可以将电荷分离效率提高3倍，并且对N2分子显示出显著的活化作用。归一化的N2光固定速率为324.86 μmol h−1 g−1（全光谱），在365 nm光照下相应的表观量子产率（AQY）达到1.1%，与文献报道相比，这是相对较高的水平。这种优异活性的起源显然归因于OV缺陷结构，其协调电荷分离效率和N2的解离吸附能力。本工作建立了OV浓度与活性之间的关系，并有助于通过优化OV浓度来构建高效的固氮光催化剂。
Photocatalytic systems capable of precisely regulating oxygen vacancy (OV) concentrations, which could help illuminate the effects of the OV concentration on N2 fixation activity, are still scarce. Here, we demonstrate that excessive OVs in TiO2, while increasing the adsorption activation capacity of N2 molecules, exhibit disappointing activity due to a decrease in charge separation efficiency. With optimized OV concentration, TiO2 can increase the charge separation efficiency 3-fold and show significant activation towards N2 molecules. The normalized N2 photofixation rate is 324.86 μmol h−1 g−1 (full spectrum) and the corresponding apparent quantum yield (AQY) under 365 nm illumination reaches 1.1%, which are relatively high levels compared to reports in the literature. The origin of this excellent activity is clearly attributable to the OV defect structures, which coordinate the charge separation efficiency and the dissociative adsorption capacity of N2. This work establishes the relationship between OV concentration and activity, and helps to construct a highly efficient nitrogen-fixing photocatalyst by optimizing the OV concentration.