Wei Ren, Chen Zhichao, Lv Hao, Zheng Xuecheng, Ge Xin, Sun Lizhi, Song Kai, Kong Chuncai, Zhang Wei, Liu Ben
Jiangsu Key Laboratory of New Power Batteries, Jiangsu Collaborative Innovation Center of Biomedical Functional Materials, School of Chemistry and Materials Science, Nanjing Normal University, Nanjing 210023, China.
Shenzhen RELX Technology Co., Ltd., Shenzhen 518108 China.
Inorg Chem. 2021 May 3;60(9):6820-6828. doi: 10.1021/acs.inorgchem.1c00721. Epub 2021 Apr 12.
Ammonia borane (AB) has received growing research interest as one of the most promising hydrogen-storage carrier materials. However, fast dehydrogenation of AB is still limited by sluggish catalytic kinetics over current catalysts. Herein, highly uniform and ultrafine bimetallic RhNi alloy nanoclusters encapsulated within nitrogen-functionalized hollow mesoporous carbons (defined as RhNi@NHMCs) are developed as highly active, durable, and selective nanocatalysts for fast hydrolysis of AB under mild conditions. Remarkable activity with a high turnover frequency (TOF) of 1294 mol mol min and low activation energy () of 18.6 kJ mol is observed at room temperature, surpassing the previous Rh-based catalysts. The detailed mechanism studies reveal that when catalyzed by RhNi@NHMCs, a covalently stable O-H bond by HO first cleaves in electropositive H* and further attacks B-H bond of AB to stoichiometrically produce 3 equiv of H, whose catalytic kinetics is restricted by the oxidation cleavage of the O-H bond. Compositional and structural features of RhNi@NHMCs result in synergic electronic, functional, and support add-in advantages, kinetically accelerating the cleavage of the attacked HO (O-H bond) and remarkably promoting the catalytic hydrolysis of AB accordingly. This present work represents a new and effective strategy for exploring high-performance supported metal-based alloy nanoclusters for (electro)catalysis.
氨硼烷（AB）作为最具潜力的储氢载体材料之一，已受到越来越多的研究关注。然而，目前催化剂上缓慢的催化动力学仍限制着AB的快速脱氢。在此，封装在氮功能化中空介孔碳中的高度均匀且超精细的双金属RhNi合金纳米团簇（定义为RhNi@NHMCs）被开发为在温和条件下用于AB快速水解的高活性、耐用且选择性的纳米催化剂。在室温下观察到其具有1294 mol mol⁻¹ min⁻¹的高周转频率（TOF）和18.6 kJ mol⁻¹的低活化能（），表现出卓越的活性，超过了先前的Rh基催化剂。详细的机理研究表明，当由RhNi@NHMCs催化时，HO形成的共价稳定O-H键首先在正电性的H*中裂解，进而攻击AB的B-H键以化学计量比产生3当量的H₂，其催化动力学受O-H键的氧化裂解限制。RhNi@NHMCs的组成和结构特征导致协同的电子、功能和载体附加优势，从动力学上加速了被攻击的HO（O-H键）的裂解，并相应地显著促进了AB的催化水解。这项工作代表了一种探索用于（电）催化的高性能负载型金属基合金纳米团簇的新的有效策略。
