Rambutan-like CoP@Mo-Co-O hollow microspheres for efficient hydrogen evolution reaction in alkaline solution

Water electrolysis has attracted a lot of attention in recent years for hydrogen production. CoP has been widely investigated as a traditional electrocatalyst for hydrogen evolution reaction (HER). However, the strong bond strength of P–H bond and weak chemical stability are still the key problems in affecting catalytic performance of CoP. In this work, we synthesized rambutan-like CoP@Mo-Co-O hollow microspheres as HER electrocatalyst, solving the two problems of CoP as electrocatalyst. Benefiting from the unique three-dimensional space structure and interface effect between CoP and Mo-Co-O, the synthesized CoP@Mo-Co-O shows a small overpotential of 62 mV at the current density of 10 mA cm−2 for HER, which is much lower than the corresponding overpotential of pure CoP microspheres (117 mV). Rambutan-like CoP@Mo-Co-O hollow microspheres also show robust long-term stability and excellent cycling stability. This work provides a new method for the design and improvement of non-precious HER electrocatalysts. We synthesized CoP@Mo-Co-O with rambutan-like hollow structure by Ostwald-ripening principle. Owing to its special three-dimensional hollow structure and interface effect, CoP@Mo-Co-O showed an excellent activity and stability for hydrogen evolution reaction in alkaline solution.