Abstract:

In order to study the synergistic effect between Mo₂C and Co on the catalytic hydrolysis of ammonia borane to hydrogen, Co-30Mo₂C/CNTs nanomaterial was prepared by a step impregnation method. The synthesized catalysts were characterized by X-ray diffraction, scanning electron microscopy and X-ray photoelectron spectroscopy, and their catalytic performance of ammonia borane hydrolysis was tested. The results showed that Co-30Mo₂C/CNTs was successfully synthesized, Co and Mo₂C were evenly dispersed around CNTs. Mo₂C grew into rod-shaped structures locally, which could play a supporting role for the agglomerated CNTs, and hence the catalyst possessed more voids and exposed more active sites. The binding energies of Co and Mo in Co-30Mo₂C/CNTs, 30Mo₂C/CNTs and 10Co/CNTs were analyzed. It was found that there was partial electron transfer, which improved the catalytic activity of Co-30Mo₂C/CNTs. The hydrogen production rate of Co-30Mo₂C/CNTs was the highest, reaching 11866. This excellent catalytic activity can be attributed to the synergistic effect between Co and Mo₂C. The addition of Mo₂C enhanced the activation of H₂O molecules. After five cycles of stability test, 75% of the activity were retained, which is of significance for the recyclability of non-precious metal catalysts.

Key words: ammonia borane, hydrogen production, catalyst, catalysis, Co, Mo₂C, catalyst support

摘要：

为了研究Mo₂C与Co之间的协同作用对催化氨硼烷水解制氢的影响，采用分步浸渍法制备了Co-30Mo₂C/CNTs复合纳米材料。采用X射线衍射、扫描电子显微镜和X射线光电子能谱对催化剂进行表征，并考察了其催化氨硼烷水解制氢性能。结果表明，实验方法成功合成Co-30Mo₂C/CNTs，Co和Mo₂C可以较均匀分散在CNTs周围，且Mo₂C可以局部生长成棒状结构，对团聚成块状的CNTs起支撑作用，使催化剂可以具有更多空隙，暴露更多活性位点。对Co-30Mo₂C/CNTs、30Mo₂C/CNTs和10Co/CNTs中的Co、Mo元素结合能进行分析，发现存在部分电子转移，影响并改善了Co-30Mo₂C/CNTs的催化活性。Co-30Mo₂C/CNTs催化氨硼烷水解产氢速率最高，可达11866，这优异的催化活性归结于Co和Mo₂C之间的协同作用，Mo₂C的添加增强了对H₂O分子的活化。经过五圈稳定性测试后，活性依然可以保留75%，这对非贵金属催化剂的可回收投入使用具有一定的研究意义。

关键词: 氨硼烷, 制氢, 催化剂, 催化作用, 钴, 碳化钼, 催化剂载体