Co@SiO 2 /C catalyst shielded by hierarchical shell for robust hydrogen production

NaBH 4 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 SiO 2 shielding cobalt-based catalysts with hierarchical active sites. Under optimized conditions, the hydrogen productivity of 18% Co@SiO 2 /C-300 is 8-fold higher than 18% Co/C catalyst without SiO 2 shell. The incorporation of SiO 2 shell enhances the partial oxidation of Co nanoparticles, resulting in the formation of a mesosphere CoO x overlayer covered by a SiO 2 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@SiO 2 /C configuration is demonstrated to enhance the activation of NaBH 4 and H 2 O and promote H 2 desorption, giving rise to a higher level of inherent activity and a relatively low reaction energy barrier.