Urchin-like cobalt hydroxide coupled with N-doped carbon dots hybrid for enhanced electrocatalytic water oxidation

The electrocatalytic water splitting into oxygen (O2) and hydrogen (H2) is one of promising technique for addressing the problem of energy shortage. Owing to the sluggish reaction kinetics for oxygen evolution reaction (OER), it is urgent to explore efficient and inexpensive OER electrocatalytic materials. Herein, a highly efficient three-dimensional (3D) hybrid of anions (Cl− and CO32−) doped cobalt hydroxide catalyst coupled with nitrogen-doped carbon dots (Co(OH)2@NCDs) is reported via a simple in situ hydrothermal method. Interestingly, the additional mass ratio of NCDs in Co(OH)2 hybrid has strong influence on the morphology of as-prepared composites. The well-defined urchin-like Co(OH)2@NCDs composite exhibits superior OER performance, achieving the low overpotential (η) of 296 mV at 10 mA cm−2 and high durability in 1 M KOH solution. The urchin-like Co(OH)2@NCDs catalyst could achieve 29-fold electrochemical active surface area than that of the pure Co(OH)2. Additionally, after coupling with NCDs, analysis result shows new Co-N charge transfer channel is generated in hybrid and an optimized electronic environment is originated from the strong electronic interaction among Co atom and NCDs, which can provide efficient charge channels for the rapid electron transfer and further improve the intrinsic activity and promote the OER kinetics. The work may endow a new strategy for the construction of excellent transition metal-based hydroxide water oxidation electrocatalysts.