State Key Laboratory of Silicon Materials, Key Laboratory of Advanced Materials and Applications for Batteries of Zhejiang Province and School of Materials Science and Engineering , Zhejiang University , Hangzhou 310027 , China.
Institute of Laser Advanced Manufacturing, Collaborative Innovation Center of High-End Laser Manufacturing Equipment , Zhejiang University of Technology , Hangzhou 310014 , China.
ACS Appl Mater Interfaces. 2018 May 9;10(18):15767-15777. doi: 10.1021/acsami.8b04011. Epub 2018 Apr 26.
Herein, we synthesize successfully ultrafine TiN nanoparticles (<3 nm in size) embedded in N-doped carbon nanorods (nano-TiN@N-C) by a facile one-step calcination process. The prepared nano-TiN@N-C exhibits superior catalytic activity for hydrogen storage in NaAlH. Adding 7 wt % nano-TiN@N-C induces more than 100 °C reduction in the onset dehydrogenation temperature of NaAlH. Approximately 4.9 wt % H is rapidly released from the 7 wt % nano-TiN@N-C-containing NaAlH at 140 °C within 60 min, and the dehydrogenation product is completely hydrogenated at 100 °C within 15 min under 100 bar of hydrogen, exhibiting significantly improved desorption/absorption kinetics. No capacity loss is observed for the nano-TiN@N-C-containing sample within 25 de-/hydrogenation cycles because nano-TiN functions as an active catalyst instead of a precursor. A severe structural distortion with extended bond lengths and reduced bond strengths for Al-H bonding when the [AlH] group adsorbs on the TiN cluster is demonstrated for the first time by density functional theory calculations, which well-explains the reduced de-/hydrogenation temperatures of the nano-TiN@N-C-containing NaAlH. These findings provide new insights into designing and synthesizing high-performance catalysts for hydrogen storage in complex hydrides.
在此，我们通过简便的一步煅烧法成功合成了嵌入氮掺杂碳纳米棒中的超细 TiN 纳米颗粒（<3nm 尺寸）（纳米-TiN@N-C）。所制备的纳米-TiN@N-C 在 NaAlH 储氢中表现出优异的催化活性。添加 7wt%的纳米-TiN@N-C 可使 NaAlH 的起始脱氢温度降低 100°C 以上。在 140°C 下，含有 7wt%纳米-TiN@N-C 的 NaAlH 在 60 分钟内迅速释放出约 4.9wt%的 H，并且在 100°C 下在 100 巴氢气下 15 分钟内完全氢化，表现出显著改善的吸/脱氢动力学。在 25 次脱氢/加氢循环内，含纳米-TiN@N-C 的样品未观察到容量损失，因为纳米-TiN 充当活性催化剂而不是前体。通过密度泛函理论计算首次证明，当 [AlH] 基团吸附在 TiN 团簇上时，Al-H 键的键长延长且键强度降低，导致严重的结构变形，这很好地解释了含纳米-TiN@N-C 的 NaAlH 的脱氢/加氢温度降低。这些发现为设计和合成复杂氢化物中储氢的高性能催化剂提供了新的见解。
