Hydrotalcite framework stabilized ruthenium nanoparticles (Ru/HTaL): efficient heterogeneous catalyst for the methanolysis of ammonia-borane

Abstract

Ruthenium nanoparticles stabilized by a hydrotalcite framework (Ru/HTaL) were prepared by following a2-step procedure comprising a wet-impregnation of ruthenium(III) chloride precatalyst on the surface of HTaL followedby an ammonia-borane (NH3 BH3) reduction of precatalyst on the HTaL surface all at room temperature. Thecharacterization of Ru/HTaL was done by using various spectroscopic and visualization methods including ICP-OES,P-XRD, FTIR, 11 B NMR, XPS, BFTEM, and HRTEM. The sum of the results gained from these analyses has revealedthe formation of well-dispersed and highly crystalline ruthenium nanoparticles with a mean diameter of 1.27 ±0.8 nm onHTaL surface. The catalytic performance of Ru/HTaL in terms of activity, selectivity, and stability was investigated inthe methanolysis of ammonia-borane (NH3 BH3 , AB), which has been considered as one of the most promising chemicalhydrogen storage materials. It was found that Ru/HTaL can catalyse methanolysis of AB effectively with an initialturnover frequency (TOF) value of 392.77 min −1at conversion (>95%) even at room temperature. Moreover, thecatalytic stability tests of Ru/HTaL in AB methanolysis showed that Ru/HTaL acts as a highly stable and reusableheterogeneous catalyst in this reaction by preserving more than 95% of its initial activity even at the 5th recycle.