Amino-group and space-confinement assisted synthesis of small and well-defined Rh nanoparticles as efficient catalysts toward ammonia borane hydrolysis

Hydrogen evolution from ammonia borane (AB) hydrolysis is of great importance considering the ever-increasing demand for green and sustainable energy. However, the development of a facile and efficient strategy to construct high-performance catalysts remains a grand challenge. Herein, we report an amino-group and space-confinement assisted strategy to fabricate Rh nanoparticles (NPs) using amino-functionalized metal-organic-frameworks (UiO-66-NH2) as a NP matrix (Rh/UiO-66-NH2). Owing to the coordination effect of amino-group and space-confinement of UiO-66-NH2, small and well-distributed Rh NPs with a diameter of 3.38 nm are successfully achieved, which can be served as efficient catalysts for AB hydrolysis at room temperature. The maximum turnover frequency of 876.7 min(-1) is obtained by using the Rh/UiO-66-NH2 with an optimal Rh loading of 4.38 wt% and AB concentration of 0.2 M at 25 degrees C, outperforming most of the previously developed Rh-based catalysts. The catalyst is also stable in repetitive cycles for five times. The high performance of this catalyst must be ascribed to the structural properties of UiO-66-NH2, which enable the formation of small and well-dispersed Rh NPs with abundant accessible active sites. This study provides a simple and efficient method to significantly enhance the catalytic performance of Rh for AB hydrolysis. (C) 2020 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.

Automated summary

This study presents a method to fabricate high-performance Rh nanoparticles catalyst using an amino-group and space-confinement assisted strategy, significantly enhancing the catalytic performance for AB hydrolysis.