A facile preparation of graphene hydrogel-supported bimetallic RuM (M: Co, Ni, Cu) nanoparticles as catalysts in the hydrogen generation from ammonia borane

Abstract

Abstract The synthesis of ultrafine well-dispersed bimetallic RuM (M: Co, Ni, Cu) nanoparticles (NPs) supported on graphene hydrogel (GH) was accomplished by a novel one-pot wet-chemical protocol that comprised the hydrothermal reduction of the mixture of graphene oxide and metal precursors by ethylene glycol (EG) in a Teflon-coated stainless-steel reactor at 180 °C. In this study, for the first time, we report the synthesis of bimetallic RuM NPs anchored on GH during the hydrothermal production of GH from graphene oxide (GH-RuM) and the catalysis of the yielded GH-Ru in the hydrolysis of ammonia borane (AB). As-synthesized GH-RuM (M: Co, Ni, Cu) nanocatalysts were characterized by using many advanced instrumental techniques including TEM, XRD, XPS, and ICP-MS. The bimetallic catalysts denoted as GH-Ru20Co80, GH-Ru30Ni70 and GH-Ru10Cu90 exhibited much higher catalytic activity compared to their Ru, Co, Ni and Cu monometallic counterparts in the hydrolytic dehydrogenation of AB. The catalytic performance of as-prepared NPs in terms of hydrogen generation rate (HGR) was achieved in the order of RuCo > RuNi > RuCu and the highest HGR calculated for the catalyst GH-Ru20Co80 reached 8911.5 mL H2 gcat −1 min−1 at room temperature with an activation energy of 52.5 kJ mol−1.