Cobalt Nanoparticles Encapsulated in the Biomass-Derived Carbon: An Efficient and Bifunctional Electrocatalyst for Overall Water Splitting

Water splitting represents a promising method for hydrogen production. However, the development of bifunctional electrocatalysts that are capable of fostering the oxygen evolution reaction (OER) and the hydrogen evolution reaction (HER) efficiently remains a significant challenge. Herein, we report an efficient and stable catalyst (Co0.15@ARC) by encapsulating cobalt nanoparticles in the biomass-derived carbon. Electrodes fabricated from Co0.15@ARC exhibit both excellent OER and HER performances in 1 M KOH solution: 320 mV for OER and 172 mV for HER to reach the current density of 10 mA cm–2. Moreover, when employed for electrochemical overall water splitting, a current density of 10 mA cm–2 is achieved at just 1.64 V, underscoring the significant potential of Co0.15@ARC for efficient overall water splitting applications. The inherited porous structures after carbonization, uniformly dispersed Co nanoparticles, and the excellent electrochemical active surface area of Co0.15@ARC collectively enhance reaction kinetics, enabling efficient performances in OER and HER. This work may provide a practical strategy for exploring efficient bifunctional electrocatalysts for overall water splitting.