MOF-derived Ni nanoparticles dispersed on monolayer MXene as catalyst for improved hydrogen storage kinetics of MgH2
MOF-derived Ni nanoparticles dispersed on monolayer MXene as catalyst for improved hydrogen storage kinetics of MgH2
复制标题
MOF 衍生的 Ni 纳米颗粒分散在单层 MXene 上作为催化剂改善 MgH2 的储氢动力学
DOI：
10.1016/j.cej.2020.127851
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发表时间：
2021-06-13
影响因子：
15.1
通讯作者：
Ding, Wenjiang
中科院分区：
文献类型：
--
作者：
Huang, Tianping;Huang, Xu;Ding, Wenjiang
制备了一种新型的催化剂--MOFs衍生的Ni纳米粒子分散在剥离的单层MXene功能载体上，并将其引入MgH 2中。当添加催化剂时，MgH 2的储氢性能得到了显著的改善。简言之，MgH 2 + 10重量% Ni@C-MXene的氢释放峰值温度为241.1 ℃，比无添加剂的MgH 2的氢释放峰值温度低约120.2 ℃。根据Kissinger方法，计算出MgH 2 + 10 wt% Ni@C-MXene复合材料的脱氢活化能为54.79 kJ mol-1，比纯MgH 2（145.08 kJ mol-1）低60%以上。在300 ° C下，MgH 2 + 10重量% Ni@C-MXene复合物在2分钟内释放约5.6重量%的氢，而对于纯MgH 2，即使脱氢时间延长至60分钟，也仅解吸2重量%的氢。此外，完全脱氢的MgH 2 + 10 wt% Ni@C-MXene表现出优异的吸氢性能，在150 ℃下在3.2 MPa氢气压力下在2 min内吸收约5 wt%的氢气。此外，在MgH 2 + 10重量% Ni@C-MXene中实现了优异的氢循环稳定性，在10次循环后容量和动力学都没有衰减。除了常规的XRD、XPS和TEM技术来阐明氢脱/吸收循环期间Ni和Ti的演变之外，更重要的是，我们进行了基于第一性原理的计算来揭示原位形成的Ti-0将如何影响Mg 2Ni/Mg 2NiH 4相互转变。除了MXene对Ni/Mg 2Ni/Mg 2NiH 4的纳米约束效应外，MXene原位生成的Ti-0还有利于Mg 2NiH 4的“氢泵”效应，这是由于在Ti 0的辅助下，形成能Ef降低。通过这种协同的“纳米限制和促进氢泵”效应，MgH 2的氢脱/吸收动力学显著加速。
A novel catalyst-MOFs derived Ni nanoparticles dispersed on exfoliated monolayered MXene functional carrier was prepared and introduced into MgH2 in this work. Striking improvements in hydrogen storage properties were achieved for MgH2 when the catalyst was added. Concisely, the hydrogen releasing peak temperature of the MgH2 + 10 wt% Ni@C-MXene is 241.1 degrees C, about 120.2 degrees C lower than that of the additive-free MgH2. According to Kissinger method, the dehydrogenation activation energy of the MgH2 + 10 wt% Ni@C-MXene composite is calculated to be 54.79 kJ mol 1, over 60% lower when compared with the pristine MgH2 (145.08 kJ mol(-1)). At 300 degrees C, the MgH2 + 10 wt% Ni@C-MXene composite releases about 5.6 wt% hydrogen within 2 min, while only 2 wt% hydrogen is desorbed even the dehydriding time prolongs to 60 min for the pure MgH2. In addition, the completely dehydrogenated MgH2 + 10 wt% Ni@C-MXene exhibits eminent hydrogen absorption performance, with approximate 5 wt% hydrogen uptaken within 2 min under 3.2 MPa hydrogen pressure at 150 degrees C. Moreover, an excellent hydrogen cycling stability is achieved in the MgH2 + 10 wt% Ni@C-MXene without decay for both capacity and kinetics after 10 cycles. Beside the regular XRD, XPS and TEM techniques to clarify the evolution of Ni and Ti during hydrogen de/absorption cycling, more importantly we performed the first principle based calculations to reveal how the in-situ formed Ti-0 would affect the Mg2Ni/Mg2NiH4 mutual transformation. Apart from the nano confinement effect of MXene for Ni/Mg2Ni/Mg2NiH4, the in-situ formed Ti-0 from MXene also favors the "hydrogen pump" effect of Mg2NiH4 due to the decreased formation energy Ef under the assistance of Ti0. Through such a synergistic "nano-confinement and facilitated hydrogen pump" effect, the hydrogen de-/ absorption kinetics of MgH2 is significantly accelerated.