Facile one-step fabrication of bimetallic Co-Ni-P hollow nanospheres anchored on reduced graphene oxide as highly efficient electrocatalyst for hydrogen evolution reaction

摘要

It is significant but challenging to develop noble-metal-free electrocatalysts exhibiting high activity and long-term stability toward hydrogen evolution reaction (HER) to satisfy the ever-increasing demand for clean and renewable energy. Herein, an environment-friendly and low-temperature electroless deposition method is developed for the synthesis of Co-Ni-P hollow nanospheres anchored on reduced graphene oxide nanosheets (Co-Ni-P/RGO). By optimizing the molar ratio of Ni/Co precursor, composition dependent electrocatalytic performances toward HER of nanostructured Co-Ni-P/RGO electrocatalyst are investigated in 1.0 M KOH solution. The results suggest that when the molar ratio of Ni/Co precursor is 3/7, as-prepared ternary Co-Ni-P/RGO electrocatalyst exhibits a remarkably enhanced HER activity in comparison to binary Ni-P/RGO and Co-P/RGO electrocatalysts, delivering a current density of 10 mA cm(-2) at the overpotential of only 207 mV. The value of Tafel slope for nanostructured Co-Ni-P/RGO electrocatalyst reveals that HER process undergoes Volmer-Heyrovsky mechanism. Besides, nanostructured Co-Ni-P/RGO electrocatalyst features superior stability under alkaline condition. The results suggest that nanostructured composite of Co-Ni-P hollow nanospheres/RGO is a potential candidate for hydrogen production through water splitting. (C) 2019 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.