Catalysis Science & Technology
·
2017
·Vol. 7
·期 9
·1838-1847
·
IF 5.773
Yi Zhang,Zhenyun Lan,Ni Jian,Zhuanghe Ren,Jianjiang Hu,Mingxia Gao,Hongge Pan,Yunhao Lu,Yongfeng Liu
In this work, we demonstrate a first attempt at understanding the catalytic mechanism of nanosized Co in reducing the dehydrogenation temperature of the Li–B–N–H hydrogen storage system by experimental observation and theoretical calculation. A nanosized Co@C composite (Co particles <10 nm) is successfully synthesized by casting a furfuryl alcohol-filled, Co-based metal–organic framework, MOF-74(Co), at 700 °C. Adding small quantities of the prepared nanosized Co@C composite significantly reduces the dehydrogenation temperature of the LiBH4–2LiNH2 system. The 5 wt% Co@C-containing sample releases approximately 10.0 wt% hydrogen at 130–230 °C with a peak temperature of 210 °C, which is reduced by 125 °C from that of the pristine sample. During hydrogen desorption, nanosized Co remains in the metallic state and only works as a catalyst to reduce the kinetic barriers of hydrogen release from the LiBH4–2LiNH2 system. Ab initio calculations reveal that the presence of a Co catalyst induces a redistribution of charge, which not only weakens the chemical H–B bonding but also enhances the electrostatic interactions between Hδ+ in the NH2 groups and Hδ− in the BH4 groups, consequently reducing the energy barriers for the formation of H2 molecules. This explains the low-temperature dehydrogenation behaviour of the Co-catalysed Li–B–N–H systems.
研究领域:
材料科学
·
能源化学
·
催化化学
·
氢能源存储
·
纳米技术
✓ 已验证
DOI
高影响因子
Journal of Energy Storage
·
2024
·
IF 8.9
Xiaohui Lu,Xinglin Yang,Jie Kong,Jianye Su,Quanhui Hou
One of the most important technologies for the sustainable development of energy in the future is solid-state hydrogen storage. This study employed etching methods to fabricate two-dimensional layered catalyst Mo 2 Ti 2 C 3 MXene, which was compared with unetched MAX phases Mo 2 Ti 2 AlC 3 and Ti 3 C 2 , as well as Mo 2 C. Through mechanical ball milling, these materials were mixed with MgH 2 to prepare composite materials, including MgH 2 + Ti 2 C 3 , MgH 2 + Mo 2 C, MgH 2 + Mo 2 Ti 2 AlC 3 , and MgH 2 + Mo 2 Ti 2 C 3 . According to the study, Mo 2 Ti 2 C 3 demonstrates the synergistic catalytic actions of Ti and Mo in contrast to Ti 2 C 3 and Mo 2 C. The composite material MgH 2 + Mo 2 Ti 2 C 3 lowers the initial dehydrogenation temperature of MgH 2 to 180 °C, which is 165 °C lower than pure MgH 2 . After 30 min at 250 °C, the dehydrogenation amount is approximately 5.85 wt%. Hydrogen absorption begins at 40 °C and reaches approximately 5.75 wt% at 150 °C. Additionally, it maintains a reversible hydrogen storage capacity of up to 96 % even after 20th cycles at 300 °C. This is because Mo 2 Ti 2 C 3 has one less layer of Al than Mo 2 Ti 2 AlC 3 , which results in a wider interlayer spacing, more active sites for MgH 2 , and facilitates hydrogen molecule dissociation and recombination.
研究领域:
材料科学
·
能源存储
·
催化
✓ 已验证
DOI
高影响因子
Materials Today Energy
·
2020
·
IF 5.604
T. Huang,X. Huang,C. Hu,J. Wang,H. Liu,Z. Ma,J. Zou,W. Ding
In this work, one-dimensional NiMoO 4 and CoMoO 4 nanorods are prepared and introduced into MgH 2 to improve its hydrogen storage properties. It is observed that the MgH 2 –NiMoO 4 system exhibits lower dehydrogenation temperature and faster kinetics than the MgH 2 –CoMoO 4 system and pure MgH 2 , indicating the superior promoting effect of NiMoO 4 over CoMoO 4 . Concretely, NiMoO 4 reacts with MgH 2 during the first dehydrogenation to in situ form Mg 2 Ni and Mo 0 , both of which are crucial factors for the following hydrogen cycling process. The ‘Mg 2 Ni/Mg 2 NiH 4 ’ mutual transformation upon hydrogen release/uptake is the well-known ‘hydrogen pump’ effect which boosts the hydrogen storage performance of MgH 2 . Moreover, theoretical calculations reveal the dual roles of Mo 0 played for the hydrogen storage in MgH 2 : i) it accelerates the hydrogen de/absorption of MgH 2 through weakening the Mg–H bonding; ii) it facilitates the mutual ‘Mg 2 Ni/Mg 2 NiH 4 ’ transformation as the formation energy of Mg 2 NiH 4 decreases under the influence of Mo 0 , which we call ‘facilitated hydrogen pump’ effect in this work. Ascribing to the collaborative action between Ni- and Mo- containing species, the hydrogen storage kinetics of MgH 2 has been accelerated.
研究领域:
材料科学
·
纳米材料
·
能源化学
·
固态储氢
·
金属氢化物
·
催化材料
·
理论计算
✓ 已验证
DOI
高影响因子
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
·
2024
·
IF 8.1
Chenxi Liang,Yan Fan,Zhenbin Wang,Yongquan Zhou,Mingjin Zhang,Cunhua Ma
Magnesium hydride (MgH 2 ) as a promising solid hydrogen syorage material has been extensively researched. but the higher separating temperature and sluggish kinetics hinder its large-scale practical application. To solve this problem, a BaZrO 3 nanocatalyst with abundant oxygen vancies is manuscripted, exerts significant improvement to the hydrogen storage performance of MgH 2 . Impressively, the onset dehydrogenation temperature of MgH 2 -10 wt% BaZrO 3 -O v composite is reduced markedly from 390 °C(for pure MgH 2 ) to 260 °C. Additionally, the composite can discharge 4.22 wt% H 2 with 10 min at 275 °C and a total dehydrogenation amouut of 5.88 wt% is achieved at 300 °C. For hydrogen absorption, the composite can rapidly recharge hydrogen at a low temperature of 150 °C and approximately 5.08 wt% H 2 can be absorbed at 275 °C within 10 min. The dehydrogenation activation energy of BaZrO 3 -O v -added MgH 2 is as low as 92.61 kJ mol −1 compared to pure MgH 2 (164.78 kJ mol −1 ). Meantime, the composite presents unexceptionable reversible kinetic performance with a retention rate of 97.35 % after 10 cycles. The excellent catalytic effects can be attributed to the in-situ generation of ZrO 2 -O v , BaO-O v and ZrH 2 from BaZrO 3 -O v during the first de-/rehydrogenation cycle, which function as nanosized active sites on MgH 2 matrix to accelerate electron transfer and provide abundant hydrogen diffusion channels. Density functional theory calculations results verify that the Mg–H length and dehydrogenation energy barrier are ameliorated through BaZrO 3 -O v . This work provides a unique perspective on modification MgH 2 by perovskiet-like BaZrO 3 -O v nanocatalyst.
研究领域:
材料科学
·
氢气储存
·
纳米催化
·
能源材料
✓ 已验证
DOI
高影响因子
Journal of Magnesium and Alloys
·
2021
·
IF 10.088
Shun Wang,Mingxia Gao,Zhihao Yao,Kaicheng Xian,Meihong Wu,Yongfeng Liu,Wenping Sun,Hongge Pan
Magnesium hydride (MgH 2 ) is one of the most promising hydrogen storage materials for practical application due to its favorable reversibility, low cost and environmental benign; however, it suffers from high dehydrogenation temperature and slow sorption kinetics. Exploring proper catalysts with high and sustainable activity is extremely desired for substantially improving the hydrogen storage properties of MgH 2 . In this work, a composite catalyst with high-loading of ultrafine Ni nanoparticles (NPs) uniformly dispersed on porous hollow carbon nanospheres is developed, which shows superior catalytic activity towards the de-/hydrogenation of MgH 2 . With an addition of 5 wt% of the composite, which contains 90 wt% Ni NPs, the onset and peak dehydrogenation temperatures of MgH 2 are lowered to 190 and 242 °C, respectively. 6.2 wt% H 2 is rapidly released within 30 min at 250 °C. The amount of H 2 that the dehydrogenation product can absorb at a low temperature of 150 °C in only 250 s is very close to the initial dehydrogenation value. A dehydrogenation capacity of 6.4 wt% remains after 50 cycles at a moderate cyclic regime, corresponding to a capacity retention of 94.1%. The Ni NPs are highly active, reacting with MgH 2 and forming nanosized Mg 2 Ni/Mg 2 NiH 4 . They act as catalysts during hydrogen sorption cycling, and maintain a high dispersibility with the help of the dispersive role of the carbon substrate, leading to sustainably catalytic activity. The present work provides new insight into designing stable and highly active catalysts for promoting the (de)hydrogenation kinetics of MgH 2 .
研究领域:
材料科学
·
催化
·
储氢
·
纳米技术
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）