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.
