The Performances Of Co₂P-Co/C Composite Catalyst For Overall Water Splitting

Hydrogen has been considered as a promising energy carrier to fulfil our need for future fuel applications.At present,hydrogen is mainly produced from fossil resources through a steam reforming process.Water electrolysis is an efficient and clean technology to generate hydrogen with high purity.Water electrolysis is considered as the most promising technology for hydrogen production.Much research has been devoted to developing efficient electrocatalysts for hydrogen production,oxygen production and bifunctionalproduction.The optimum electrocatalysts can drive down the energy costs needed for water splitting via lowering the overpotential.A number of cobalt-based materials have been developed over past years.This work used carbonizing-phosphating method to get Co@Co₂P@C-B catalyst.The resulting material of well-defined mesoporosity and a high specific surface area?209.438 m2/g?can be directly employed as a bifunctional and flexible working electrode for both hydrogen and oxygen evolution reactions,showing superior activities as compared with noble metal benchmarks and state-of-the-art transition-metal-based catalysts.The main conslusions are listed as follows:?1?Overall Water Splitting:A further step is taken towards an alkaline electrolyzer that can achieve a current density of 10 mA/cm-2 at a voltage around 1.83 V/RHE over a long-term operation,better than the combination of Ir/C-Pt/C.?2?Hydrogen evolution reaction:A current density of 10 mA/cm-2 was generated at an overpotential of only 1.57 V/RHE in 0.1 M KOH for a Co@Co₂P@C-B nanorod-based electrode,which was competitive with commercial Ir/C.The Tafel slope for Co@Co₂P@C-B was only 88 mV dec-1.?3?Oxygen evolution reaction:Our experimental results show significantly enhanced performance for such engineered nanostructures due to the synergistic effect from nanoparticles encapsulation and phosphorus doping on carbon structures.The obtained Co@Co₂P@C-B modified cathode exhibits small overpotentials of only 420 mV/RHE at 10 mA/cm-2,respectively,with a low Tafel slope of 193 mV dec-1 in 0.1 M KOH.In addition,encapsulation by P-doped carbon effectively prevent nanoparticle from corrosion,exhibiting nearly unfading catalytic performance after 5000 CV scans testing.