An experimental and theoretical investigation of the enhanced effect of Ni atom-functionalized MXene composite on the mechanism for hydrogen storage performance in MgH2

作者：Zhiqiang Lan, Jiakun Yang, Xiaobin Wen, Ruojiang Liu, Ziqi Liu, Sizhi Ding, Hua Ning, Haizhen Liu, I.P. Jain, Jin Guo · 发表于：Journal of Magnesium and Alloys · 年份：2024 · DOI：10.1016/j.jma.2024.11.003 · 被引用次数：20 · 研究领域：Hydrogen Storage and Materials、MXene and MAX Phase Materials、Ammonia Synthesis and Nitrogen Reduction

• MXene supported Ultrafine single-atom nickel (Ni@Nb 2 C)nanocomposites was prepared. • The addition of Ni can enhance the catalytic activity of Nb 2 C. • Ni@Nb 2 C reduces the hydrogen uptake/release temperature of MgH 2 . • The Ni@Nb 2 C-doped MgH 2 composite exhibits excellent hydrogen storage kinetics. The deposition of ultrafine single-atom nickel particles on Nb 2 C (MXene) was successfully achieved using a wet chemistry method to synthesize Ni@Nb 2 C composite. This study explored the effect of Ni@Nb 2 C on the hydrogen absorption and desorption properties of MgH 2 through theoretical calculations and experimental investigations. Under the catalytic action of Ni@Nb 2 C, the initial dehydrogenation temperature of MgH 2 was reduced by 121°C, with approximately 4.26 wt.% of H 2 desorbed at 225°C in 100 min. The dehydrogenation activation energy of the MgH 2 + Ni@Nb 2 C composite dropped to 86.7 kJ·mol −1 , a reduction of 60.5 kJ·mol −1 compared to pure MgH 2 . Density functional theory calculations indicated that the incorporation of Ni@Nb 2 C enhanced the performance of MgH 2 performance by improving interactions among Nb 2 C, Ni, Mg, and H atoms. In the Ni@Nb 2 C + MgH 2 system, the lengths of Mg-H bonds (1.91–1.99 Å) were found to be longer than those observed in pure MgH 2 (1.71 Å). The dehydrogenation energy for this system (1.08 eV) was lower than that for Nb 2 C (1.52 eV). These findings suggest that the synergistic effect of Ni and Nb 2 C significantly enhances t...