Low-temperature NO trapping on alkali or alkaline earth metal modified TiO2 photocatalyst
Low-temperature NO trapping on alkali or alkaline earth metal modified TiO2 photocatalyst
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碱金属或碱土金属改性 TiO2 光催化剂的低温 NO 捕集
DOI：
10.1016/j.cattod.2018.07.045
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发表时间：
2019
期刊：
影响因子：
5.3
通讯作者：
Tanaka Tsunehiro
中科院分区：
文献类型：
--
作者：
Tamai Kazuki;Hosokawa Saburo;Asakura Hiroyuki;Teramura Kentaro;Tanaka Tsunehiro
低温氮氧化物捕集表现在碱金属（Na，K，Rb和Cs）或碱土金属（Mg，Ca，Sr和Ba）改性的TiO 2光催化剂（M-TiO 2）。该改性提高了裸TiO 2的NOx捕集效率和NOx存储容量（NSC）。NSC依赖于改性的金属物种。Cs-TiO 2和Ba-TiO 2表现出与传统NOx捕集催化剂Pt/Ba/Al 2 O3（176 μ mol g − 1）相当的容量（分别为179和187 μmol g −1）。XRD和XPS分析表明，M-TiO_2的结构和表面性质均发生了变化。碱金属TiO 2促进了TiO 2的烧结，并显著提高了TiO 2表面的电子密度;碱土金属TiO 2抑制了TiO 2的烧结，但表面性质变化不大。通过对合成催化剂的NOx-TPD测试，评价了催化剂对NOx的吸附强度。对于碱土金属TiO 2，较强的NOx吸附增加NOx捕集效率。此外，原位DRIFT测量清楚地显示了M-TiO 2中吸附的NOx物种之间的差异。碱土金属TiO 2对NOx的捕集作用主要集中在Ti位上，而碱金属TiO 2对NOx的捕集作用主要集中在碱金属位上。碱土金属TiO 2在Ti位上捕集NO x可以在低温下高效地光催化捕集NO x。
Low-temperature NOxtrapping was demonstrated on alkali (Na, K, Rb, and Cs) or alkaline earth metal (Mg, Ca, Sr, and Ba)-modified anatase TiO2photocatalysts (M-TiO2). The modification enhanced the NOx-trapping efficiency of bare TiO2as well as the NOxstorage capacity (NSC). The NSC depended on the modified metal species. Cs-TiO2and Ba-TiO2showed a comparable capacity (179 and 187 μmol g−1, respectively) with a conventional NOx-trapping catalyst, Pt/Ba/Al2O3(176 μmol g−1). XRD and XPS revealed the modification effect on the structures and the surface properties of M-TiO2. Alkali TiO2promoted the sintering of TiO2and significantly increased the electron density of the TiO2surface, while alkaline earth TiO2suppressed the sintering and slightly changed the surface properties. The adsorption strength of NOxwas evaluated from the NOx-TPD of the as-synthesized catalyst. For alkaline earth TiO2, stronger NOxadsorption increased the NOx-trapping efficiency. In addition, in-situ DRIFT measurements clearly showed the difference between adsorbed NOxspecies in M-TiO2. Alkaline earth TiO2traps NOxon Ti sites, whereas alkali TiO2traps NOxmainly on alkali sites. NOxtrapping on Ti sites for alkaline earth TiO2was effective for photocatalytic NOxtrapping with high efficiency at low temperature.