Co@SiO2/C catalyst shielded by hierarchical shell for robust hydrogen production

Abstract

NaBH4 hydrolysis under mild conditions is a promising solution for mobile hydrogen applications. However, the design and synthesis of cost-effective catalysts with sufficiently high activity and stability remain challenging. Herein, we report a facile approach to construct a series of SiO2 shielding cobalt-based catalysts with hierarchical active sites. Under optimized conditions, the hydrogen productivity of 18% Co@SiO2/C-300 is 8-fold higher than 18% Co/C catalyst without SiO2 shell. The incorporation of SiO2 shell enhances the partial oxidation of Co nanoparticles, resulting in the formation of a mesosphere CoOx overlayer covered by a SiO2 shell on Co particles. Meanwhile, the cobalt oxide on Co NPs could remain stable under reductive reaction conditions. The unique structural and electronic properties of the Co@SiO2/C configuration is demonstrated to enhance the activation of NaBH4 and H2O and promote H2 desorption, giving rise to a higher level of inherent activity and a relatively low reaction energy barrier.