Experimental and computational insight into the role of cobalt and phosphorus in boosting Volmer and Heyrovsky steps of Ni in alkaline hydrogen evolution reaction

Deep insight into the role of doped hetero atoms in boosting the alkaline hydrogen evolution reaction (HER) activity is of significance for designing the low-cost electrocatalysts to produce hydrogen. Herein, we designed, synthesized, and optimized the Co and P co-doped Ni (NCP) electrocatalysts and evaluated the HER performance in alkaline medium. It was found that the NCP exhibited the enhanced hydrogen evolution performance, only need an overpotential of 57.0 mV to afford 10 mA·cm−2. The calculation results of density functional density revealed that the doped P plays an important role in modulating electron distribution of Ni and Co atoms, which reduce the Gibbs free energy of water molecule dissociation at Co sites in Volmer step, and optimize the ab/desorption of hydrogen at Ni site that bonded to P and Ni atoms in Heyrovsky step, respectively. The obtained results are conductive to understanding the electrocatalytic mechanism of alkaline HER.