Polyaniline Derived N-Doped Carbon-Coated Cobalt Phosphide Nanoparticles Deposited on N-Doped Graphene as an Efficient Electrocatalyst for Hydrogen Evolution Reaction

The development of highly efficient and durable non-noble metal electrocatalysts for the hydrogen evolution reaction (HER) is significant for clean and renewable energy research. This work reports the synthesis of N-doped graphene nanosheets supported N-doped carbon coated cobalt phosphide (CoP) nanoparticles via a pyrolysis and a subsequent phosphating process by using polyaniline. The obtained electrocatalyst exhibits excellent electrochemical activity for HER with a small overpotential of -135 mV at 10 mA cm(-2) and a low Tafel slope of 59.3 mV dec(-1) in 0.5 M H2SO4. Additionally, the encapsulation of N-doped carbon shell prevents CoP nanoparticles from corrosion, exhibiting good stability after 14 h operation. Moreover, the as-prepared electrocatalyst also shows outstanding activity and stability in basic and neutral electrolytes.