An improved preparation of graphene supported ultrafine ruthenium (0) NPs: Very active and durable catalysts for H-2 generation from methanolysis of ammonia borane

摘要

An improved route was developed to prepare graphene supported ultrafine Ru nanoparticles (NPs) by two steps in this work. Exfoliated graphene oxide suspensions were firstly prepared by the intercalated reaction of tetrabutylammonium hydroxide (TBAOH) with graphite oxide (GO), followed by the deposition of Ru NPs to obtain Ru/graphene. The as-prepared Ru/graphene was characterized by many techniques, including TEM, SEM, EDX, UV Vis, Raman spectra, and XPS. It was found that remarkably uniform and dispersed Ru NPs with sizes of about 1.57 nm that possessed high crystallinity were supported on the surface of exfoliated graphene sheet. The catalytic activity and reusability of Ru/graphene were evaluated by the methanolysis of ammonia borane (H3NBH3, AB) at ambient temperature. Results showed that Ru/graphene was a very active and stable catalyst as it provided 35,600 total turnovers over a period of 300 h before deactivation in the methanolysis of AB at 20 degrees C. The first-order reaction kinetic modes of both catalyst amount and AB concentration were constructed for the AB methanolysis reaction catalyzed by Ru/graphene, and the apparent activation energy (Ea) for the methanolysis dehydrogenation of AB was 54.1 +/- 2 kJ/mol. Additionally, the Ru/graphene catalyst also demonstrated satisfactory durable stability for H-2 generation from the methanolysis dehydrogenation of AB. In principle, the unique strategy could be also applied to, but not limited to other metal or alloy NPs in fabrication of highly active graphene-based nanocatalysts. Copyright (C) 2015, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.