摘要
It is crucial to develop high-performance and cost-effective bifunctional electrocatalysts for both oxygen evolution reaction(OER)and hydrogen evolution reaction(HER)toward overall water splitting.Herein,a unique heterostructure of reduced graphene oxide(rGO)and CoNiO_(2) nanosheets directly grown on nickel foam(NF)were successfully fabricated and applied as a kind of highly efficient bifunctional electrocatalyst.The optimum CoNiO_(2)@rGO/NF electrode exhibits excellent elec-trocatalytic OER performance with an overpotential of only 272 mV to drive a current density of 100 mA·cm^(−2),and HER performance with an overpotential of 126 mV to achieve a current density of 10 mA·cm^(−2).Meanwhile,the electrodes also display outstanding long-term stability for OER and HER with negligible activity and morphology degradation after at least 40 h testing.Furthermore,when employed as both cathode and anode for overall water splitting,CoNiO_(2)@rGO/NF elec-trode only requires 1.56 V at 10 mA·cm^(−2) and operates stably for over 40 h,which is among the best performing Co-based and Ni-based non-precious metal electrocatalysts.Detailed characterizations reveal that the extraordinary electrocatalytic performance should be attributed to the synergistic effect of the unique heterostructure of CoNiO_(2) nanosheets and rGO for increasing the electrode conductivity and integrity,ultrasmall primary particle size for providing larger electrode/electrolyte contact area and abundant active sites,and three-dimensional(3D)conductive networks for facilitating the electrochemical reaction.
基金
This work was financially supported by National Nature Science Foundation of China(Grant No.21905306)
Natural Science Foundation of Hunan Province(Grant No.2020JJ5694).
