One-pot synthesis of graphene hydrogel-anchored cobalt-copper nanoparticles and their catalysis in hydrogen generation from ammonia borane

Authors: IBTIHEL ZAIER, ÖNDER METİN

Abstract: We reported a facile one-pot synthesis of bimetallic CoCu nanoparticles (NPs) anchored on graphene hydrogel (GH-CoCu) as catalysts in hydrogen generation from the hydrolysis of ammonia borane (HAB). The presented novel one-pot method composed of the reduction of the mixture of graphene oxide, cobalt(II), and copper(II) acetate tetrahydrates by aqueous ethylene glycol solution in a teflon-coated stainless-steel reactor at 180 °C. The structure of the yielded GH-CoCu nanocatalysts was characterized by TEM, SEM, XRD, XPS, and ICP-MS. This is the first example of both the synthesis of bimetallic CoCu NPs anchored on GH and the testing of a hydrothermally prepared noble metal-free GH-bimetallic nanocomposites as catalysts for the HAB. The presented in situ synthesis protocol allowed us to prepare different metal compositions and investigating their catalysis in the AB hydrolysis, where the best catalytic activity was accomplished by the GH-Co₃₃Cu₆₇ nanocatalysts. The obtained GH-CoCu nanocatalysts exhibited a remarkable catalytic performance in the HAB by providing the highest hydrogen generation rate of 1015.809 ml H₂ g_catalyst^-1 min^-1 at room temperature. This study has a potential to pave a way for the development of other GH-based bimetallic nanocatalysts that could be used in different applications.

Keywords: Graphene hydrogel, cobalt-copper, nanoparticles, nanocatalyst, ammonia borane, hydrogen generation

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