Protection and confinement effect of carbon on Co/ Co_xO_y nano-catalyst for efficient NaBH_4 hydrolysis

摘要

The hydrolysis of sodium borohydride (NaBH4) over catalysts is a promising method to produce hydrogen. Although Co-based catalysts exhibit high activity for NaBH4 hydrolysis, they are still far from satisfying practical applications, especially their poor durability in alkaline media. Herein, a carbon shell structure was designed and synthesized to improve the stability of the mixture of Co-0 and CoxOy nanofilms (Co/CoxOy@C) during NaBH4 hydrolysis via a facile polymerization-pyrolysis strategy with Co/CoxOy nanofilms as the precursor. As a result, the Co/CoxOy @C catalyst can achieve a remarkable H-2 generation rate of 4348.6 mL min(-1)g(Co)(-1) with a low activation energy of 43.6 kJ mol(-1), which is superior to most previously reported catalysts. Moreover, the catalyst shows high stability with an H-2 generation-specific rate of 79% after five cycles. The excellent performance of carbon substrate can well prevent the agglomeration of Co-based nanoparticle and improve the corrosion resistance of the active Co to BO2- and OH-. This work would widen the road for the preparation of nanoconfined catalysts, which has prospective application potentials for H-2 production from NaBH4 hydrolysis. (C) 2022 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.