论文简介如下：
本研究通过一步球磨法制备了双过渡金属氢化物纳米片(NbVH NPs)，并将其成功负载于Ti3C2的层间结构及表面上。基于双过渡金属的协同催化作用，Mg(BH4)2的析氢动力学大幅提升。NbVH NPs@Ti3C2催化后的Mg(BH4)2放氢温度由248 °C降低至105.7 °C。同时，当温度升高至330 °C时的放氢量由4.2 wt%提升至9.07 wt%，展现出极大的动力学性能提升。在250 °C进行可逆性能测试时， NbVH NPs@Ti3C2催化后的Mg(BH4)2可逆性大幅提升，在第二次循环中保持5.98 wt%的可逆性并在10次循环后保持4.35 wt%的可逆性。较原始Mg(BH4)2在两次循环后可逆性衰减至2.6 wt%有了巨幅提升。Mg(BH4)2动力学及热力学的性能提升源于NbVH NPs提供的双向氢泵作用，产生的氢溢流和氢扩散作用促进了氢气的解吸和耦合。
Bimetallic niobium vanadium hydride nanoparticles (NbVH NPs) anchored on Ti3C2 were synthesized using a facile ball milling method as an effective catalyst for the dehydrogenation kinetics and reversibility of Mg(BH4)2. It was found that the onset dehydrogenation temperature of the Mg(BH4)2 + 30NbVH NPs@Ti3C2 composite was 105.7 °C and released 9.07 wt% of hydrogen at 330 °C, while undoped Mg(BH4)2 only released 4.2 wt% of H2 from 248 °C to 330 °C. Additionally, the Mg(BH4)2 + 30NbVH NPs@Ti3C2 composite achieved remarkable hydrogen release of over 9.44 wt% at a temperature as low as 230 °C, indicating unexpected dehydrogenation kinetics. In the reversible hydrogen desorption tests, Mg(BH4)2 + 30NbVH NPs@ Ti3C2 released 5.98 wt% of H2 in the 2nd cycle at 250 °C and maintained a reversible capacity of 4.35 wt% after 10 cycles, demonstrating a remarkable enhancement in reversibility. The enhancement in the dehydrogenation kinetics of Mg(BH4)2 could be attributed to the greatly reduced activation energies from 343 kJ·mol?1 and 138.3 kJ·mol?1 to 103.7 kJ·mol?1 and 124 kJ·mol?1. Investigations on the evaluation of catalyst and Mg(BH4)2 during reversible hydrogen storage have revealed that NbVH NPs actually acted as a “bidirectional hydrogen pump”, facilitating both the hydrogen release and uptake from Mg(BH4)2. This strategy of multi-component hydrides may show a new way to design effective catalysts for solid-state hydrogen storage materials.
