Beijing Key Laboratory of Environmental Science and Engineering, School of Materials Science and Engineering, Beijing Institute of Technology , Beijing 100081, P.R. China.
Collaborative Innovation Center of Electric Vehicles in Beijing, Beijing 100081, P.R. China.
ACS Appl Mater Interfaces. 2017 Sep 20;9(37):31977-31984. doi: 10.1021/acsami.7b10043. Epub 2017 Sep 5.
The lightweight compound material NaNH-NaBH is regarded as a promising hydrogen storage composite due to the high hydrogen density. Mechanical ball milling was employed to synthesize the composite NaNH-NaBH (2/1 molar ratio), and the samples were investigated utilizing thermogravimetric-differential thermal analysis-mass spectroscopy (TG-DTA-MS), X-ray diffraction (XRD), and Fourier transform infrared spectroscopy (FTIR) analyses. The full-spectrum test (range of the ratio of mass to charge: 0-200) shows that the released gaseous species contain H, NH, BH, and N in the heating process from room temperature to 400 °C, and possibly the impurity gas BH also exists. The TG/DTA analyses show that the composite NaNH-NaBH (2/1 molar ratio) is conductive to generate hydrogen so that the dehydrogenation process can be finished before 400 °C. Moreover, the thermal decomposition process from 200 to 400 °C involves two-step dehydrogenation reactions: (1) Na(NH)BH hydride decomposes into NaBN and H (200-350 °C); (2) remaining Na(NH)BH reacts with NaBH and NaBN, generating Na, BN, NH, N, and H (350-400 °C). The better mechanism understanding of the thermal decomposition pathway lays a foundation for tailoring the hydrogen storage performance of the composite complex hydrides system.
轻质化合物 NaNH-NaBH 因其高储氢密度而被认为是一种很有前途的储氢复合材料。采用机械球磨法合成了复合 NaNH-NaBH（2/1 摩尔比），并利用热重-差示热分析-质谱联用（TG-DTA-MS）、X 射线衍射（XRD）和傅里叶变换红外光谱（FTIR）分析对样品进行了研究。全谱测试（质荷比范围：0-200）表明，在从室温加热到 400°C 的过程中，释放的气态物质包含 H、NH、BH 和 N，并且可能存在杂质气体 BH。TG/DTA 分析表明，复合 NaNH-NaBH（2/1 摩尔比）有利于产生氢气，从而在 400°C 之前完成脱氢过程。此外，200-400°C 的热分解过程涉及两步脱氢反应：（1）Na(NH)BH 氢化物分解为 NaBN 和 H（200-350°C）；（2）剩余的 Na(NH)BH 与 NaBH 和 NaBN 反应，生成 Na、BN、NH、N 和 H（350-400°C）。对热分解途径的更好的机理理解为定制复合复杂氢化物体系的储氢性能奠定了基础。
