Graphene oxide co-doped with nitrogen and sulfur and decorated with cobalt phosphide nanorods: An efficient hybrid catalyst for electrochemical hydrogen evolution

- A facile thermal decomposition method has been used to synthesize CoP nanorods in situ grown on graphene oxide co-doped with N and S atoms.
- CoP/NSGO catalyst exhibits excellent activity and stability for HER.
- CoP/NSGO catalyst exhibits higher catalytic activity than CoP/NGO and CoP/GO catalysts.
- The formation of pyridinic N, pyrrolic N and thiophene S species contribute to the high catalytic activity.
- The co-doping of graphene with two heteroatoms is an effective way to improve the HER performance.

The construction of efficient and robust CoP-based hybrid catalysts for the hydrogen evolution reaction (HER) remains challenging. In this work, a facile thermal decomposition method has been used to synthesize CoP nanorods (NRs) in situ grown on graphene oxide co-doped with nitrogen and sulfur (CoP/NSGO) as a high activity and stability hybrid catalyst for the HER. The catalysts were characterized by X-ray diffraction, Raman spectroscopy, scanning electron microscopy, transmission electron microscopy, X-ray photoelectron spectroscopy and N2 sorption. The as-synthesized CoP/NSGO catalyst exhibited much higher HER performance than CoP/NGO and CoP/GO catalysts, indicating the positive role of N, S co-doping into the graphene frame. The formation of pyridinic N and pyrrolic N species as well as thiophene S species, which acted as novel active centers and benefited the suitable chemisorption of intermediates for catalyzing HER, improved the catalytic activity. Our current research indicates that both nitrogen and sulfur atoms played an important role in enhancing the HER performance for CoP-based catalysts.

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