Tungsten(VI) oxide supported rhodium(0) nanoparticles; highly efficient catalyst for H2 production from dimethylamine borane

It reports the preparation and characterization of tungsten(VI) oxide supported rhodium(0) nanoparticles (Rh-0/WO3 NPs) being used as catalysts in releasing H-2 from dimethylamine borane (DMAB). The reducible nature of WO3 plays a significant role in the catalytic efficiency of rhodium(0) nanoparticles in the dehydrogenation of DMAB. The Rh-0/WO3 NPs were in-situ generated from the reduction of Rh2+ ions on the surface of WO3 during the catalytic dehydrogenation of dimethylamine borane in toluene and isolated from the reaction solution after the dehydrogenation to be characterized by using SEM, TEM, XPS, ATR-IR and XRD. The results reveal the formation of Rh-0 NPs with a mean particle size of 1.92 +/- 0.34 nm dispersed on the surface of tungsten(VI) oxide. Rh-0/WO3 NPs are found to be very active catalyst releasing 1.0 equiv. H-2 per mole of dimethylamine borane under ambient conditions. Among the various WO3 supported Rh-0 NPs with different metal loadings, the sample with 0.1% wt. Rh provide the record catalytic activity (TOF = 2816 h(-1)) which is one of the highest value ever reported for rhodium-based catalysts in H-2 generation from DMAB at 60.0 +/- 0.5 degrees C. Rh-0/WO3 NPs were also reusable catalyst in dehydrogenation of DMAB retaining 55% of their initial catalytic activity in the 3rd run of the dehydrogenation reaction. Control experiments were performed at various catalyst concentrations and temperatures to investigate the kinetics of dehydrogenation and to calculate the activation parameters for the reaction. (C) 2021 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.

Automated summary

The study focuses on the preparation and characterization of tungsten(VI) oxide supported rhodium(0) nanoparticles (Rh-0/WO3 NPs) used as catalysts for releasing H-2 from dimethylamine borane (DMAB). Rh-0/WO3 NPs exhibit high catalytic activity, with the sample containing 0.1% wt. Rh showing the highest catalytic activity (TOF = 2816 h(-1)). Additionally, the Rh-0/WO3 NPs show good reusability, retaining 55% of their initial catalytic activity after being reused in the dehydrogenation reaction.