Non-noble trimetallic Cu-Ni-Co nanoparticles supported on metal-organic frameworks as highly efficient catalysts for hydrolysis of ammonia borane

Abstract

Highly dispersed non-noble trimetallic Cu-Ni-Co nanoparticles can be successfully immobilized onto the pores of the metal-organic framework, MIL-101, by a simple solvent evaporation method. The Cu-Ni-Co@MIL-101 nanoparticles exhibit excellent catalytic effect on the hydrolysis of ammonia borane at 25 °C. Compared to their bimetallic and monometallic counterparts, Cu-Ni-Co trimetallic catalysts display superior catalytic activity. Careful investigation reveals that Cu0.8Ni0.1Co0.1@MIL-101 (Cu:Ni:Co atomic ratio = 8:1:1) displays a total turnover frequency (TOF) value of 72.1 molH2 molcat−1 min−1. This is the highest TOF value reported for non-noble metal catalysts to date and is even superior to values afforded by some noble metal catalysts (Au, Pt and Pd). The apparent activation energy of Cu0.8Ni0.1Co0.1@MIL-101 can be as low as 29.1 kJ mol−1. This remarkable enhancement in catalytic performance is attributed to the large catalyst surface as well as the synergetic effect between Cu, Ni, and Co supported on MIL-101. This study provides a new strategy for the preparation of high performance non-noble metal catalysts for the practical hydrolysis of hydrogen storage systems, thereby fast-tracking the application of ammonia borane in fuel cells.