Synthesis of SrFexTi1-xO3-delta nanocubes with tunable oxygen vacancies for selective and efficient photocatalytic NO oxidation
Synthesis of SrFexTi1-xO3-delta nanocubes with tunable oxygen vacancies for selective and efficient photocatalytic NO oxidation
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具有可调节氧空位的 SrFexTi1-xO3-delta 纳米立方体的合成，用于选择性和高效光催化 NO 氧化
DOI：
10.1016/j.apcatb.2018.07.076
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发表时间：
2018
期刊：
影响因子：
--
通讯作者：
Lee Shuncheng
中科院分区：
文献类型：
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作者：
Zhang Qian;Huang Yu;Peng Shiqi;Huang Tingting;Cao Jun-ji;Ho Wingkei;Lee Shuncheng
金属氧化物中的氧空位对许多光催化反应的活性和选择性起着至关重要的作用，但对NO在富含缺陷的光催化剂表面的氧化机理却鲜有人讨论。在这里，我们提供了详细的洞察力的氧空位操纵的外部Fe3+取代在SrTiO_3晶格和光催化性能的NO减少。特别是水热合成的SrFexTi1-xO3-δ纳米立方体(记为SFTO-HYD样品)，而不是浸渍-后退火样品，促进了氧空位的形成，促进了O2吸附和超氧阴离子自由基(DotO2−)的形成。SFTO-HYD(x = 5%)样品在氙灯(λ>；420 nm)下的脱氮活性和选择性显著高于纯的钛酸锶、P25和浸渍掺杂的样品，强调了共存的Fe~(3+)位和氧空位所起的重要作用。漫反射红外光谱(DRIFTS)力学分析表明，SrTiO_3为NO的暗吸附和光反应提供了Lewis酸性中心，最终产物为硝酸盐；取代的Fe3+中心为NO的吸附和光反应提供了更多的活性中心，增加了自由基数。本研究加深了对缺陷表面光催化还原NO的认识，也为合成高效、高选择性的环境修复光催化剂提供了一种简单、经济的策略。
Oxygen vacancies of metal oxides play critical roles in tunning activity and selectivity for many photocatalysis mediated reactions, yet the mechanism of NO oxidation on defect enriched photocatalyst surface is seldomly discussed. Herein, we provide detailed insight into the relationship between oxygen vacancy manipulation by extrinsic Fe3+substitution in SrTiO3host lattice and the photocatalytic performance of NO abatement. In particular, the hydrothermal synthesized SrFexTi1-xO3-δnanocubes (denoted as SFTO-hyd sample) rather than the impregnated-post annealing sample, enabled oxygen vacancy formation, and promoted O2adsorption and superoxide anion radicals (radical dotO2−) formation. The SFTO-hyd (x = 5%) sample showed remarkably higher NO removal activity and selectivity under Xe lamp (λ> 420 nm), in comparison with the pristine SrTiO3, P25 and impregnation-doped SFTO sample, underlining the important roles played by coexisted Fe3+sites and oxygen vacancies. Thein situdiffuse reflectance IR spectroscopy (DRIFTS) mechanically revealed that SrTiO3provided Lewis acidic sites for NO dark adsorption and photoreaction with nitrates as final products; the substitutional Fe3+sites provided more active sites for NO adsorption and photoreaction with enhanced number of radicals. This study deepens the understanding of photocatalytic NO abatement on defective surface, and may also provide a simple and cost effective strategy for synthesizing efficient and selective photocatalysts for environmental remediation.