NaH doped TiO2 as a high-performance catalyst for Mg/MgH2 cycling stability and room temperature absorption
NaH doped TiO2 as a high-performance catalyst for Mg/MgH2 cycling stability and room temperature absorption
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NaH 掺杂 TiO2 作为高性能催化剂，可提高 Mg/MgH2 循环稳定性和室温吸收性能
DOI：
10.1016/j.jma.2021.11.005
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发表时间：
2021-12
影响因子：
17.6
通讯作者：
Chen Ping
中科院分区：
文献类型：
--
作者：
Bolarin Joshua Adedeji;Zhang Zhao;Cao Hujun;Li Zhi;He Teng;Chen Ping
研究了NaH掺杂纳米TiO 2（NaTiOxH）对MgH 2储氢性能的催化作用。该催化剂的制备包括球磨NaH与TiO 2 3 hr。将5 wt% NaTiO xH粉末添加到MgH 2中可将其操作温度降低至185 °C，这比不含添加剂的球磨MgH 2低110 °C。该复合材料在290 °C下15 min内可显著解吸1.72wt%的H2，在室温下50 bar H2下45 min内可再吸收1.45wt%的H2。MgH 2脱氢反应在57 kJ/mol下被催化剂活化。更重要的是，添加2.5wt%NaTiOxH催化剂有助于MgH 2在300 °C下在475小时内在100次循环后可逆地产生约6.1wt%H2。微观结构的研究表明，催化的MgH 2复合材料之间存在着牢固的接触NaTiOxH和MgH 2颗粒。同时，NaTiOxH催化剂由催化活性的Ti 3 O 5和制备过程中原位释放的“棒状”Na 2 Ti 3 O 7物种组成，这些活性物种可以为改善MgH 2吸附过程提供多种氢扩散途径。此外，元素表征确定了钛（Ti<4+）的还原价态，其显示出与H2插入和移除一致的某种可逆性。这种现象被认为是通过在有缺陷的（TiO 2-x）催化剂中产生和消除氧空位来增强Mg/MgH 2电子的迁移率。因此，我们的研究结果使MgH 2更接近实际应用。
This paper presents the catalytic effect of NaH doped nanocrystalline TiO2(designated as NaTiOxH) in the improvement of MgH2hydrogen storage properties. The catalyst preparation involves ball milling NaH with TiO2for 3 hr. The addition of 5 wt% NaTiOxH powder into MgH2reduces its operating temperature to ∼185 °C, which is ∼110 °C lower than the additive-free as-milled MgH2. The composite remarkably desorbs ∼7.2 wt% H2within 15 min at ∼290 °C and reabsorbs ∼4.5 wt% H2in 45 min at room temperature under 50 bar H2. MgH2dehydrogenation is activated at 57 kJ/mol by the catalyst. More importantly, the addition of 2.5 wt% NaTiOxH catalyst aids MgH2to reversibly produce ∼6.1 wt% H2upon 100 cycles within 475 hr at 300 °C. Microstructural investigation into the catalyzed MgH2composite reveals a firm contact existing between NaTiOxH and MgH2particles. Meanwhile, the NaTiOxH catalyst consists of catalytically active Ti3O5, and “rod-like” Na2Ti3O7species liberatedin-situduring preparation; these active species could provide multiple hydrogen diffusion pathways for an improved MgH2sorption process. Furthermore, the elemental characterization identifies the reduced valence states of titanium (Ti<4+) which show some sort of reversibility consistent with H2insertion and removal. This phenomenon is believed to enhance the mobility of Mg/MgH2electrons by the creation and elimination of oxygen vacancies in the defective (TiO2-x) catalyst. Our findings have therefore moved MgH2closer to practical applications.
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影响因子：
4.1
作者：
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影响因子：
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