Electrocatalytic Investigation of M@Pd(M=Ni,Co,Cu)Core-Shell Nanostructure Supported on N,S-Doped Reduced Graphene Oxide towards Hydrogen and Oxygen Evolution Reaction

摘要

The strong affinity of palladium(Pd)towards hydrogen is the main challenge for hydrogen desorption application.Therefore,in this report,we synthesized nickel,copper,and cobalt core and palladium shell nanostructure supported on nitrogen,sulfur-doped reduced graphene oxide(M@Pd/N,S-rGO,M=Ni,Cu,Co)by hydrothermal method followed by reduction of the metal nanoparticles using modified polyol method.Using X-ray diffraction(XRD),Raman spectroscopy,High resolution transmission electron microscope(HRTEM),Field emission scanning electron microscope(FESEM),and X-ray photoelectron spectroscopy(XPS),the physicochemical properties of the synthesized sample was investigated.The results confirm strong interactions between M@Pd and higher surface area support that could enhance electrocatalytic activity towards hydrogen evolution reaction(HER)and oxygen evolution reaction(OER).Among the synthesized electrocatalyst,Ni@Pd/N,S-rGO exhibits higher electrocatalytic activity with small over potential 0.035 V and 0.2 V at 10 mA/cm~2 and a Tafel slope value of 39 mVdec~(-1)and 34 mVdec~(-1)for HER and OER,respectively.The Ni@Pd/N,SrGO electrocatalyst demonstrated excellent stability with a negligible current decrease for 12 h.The Cdl calculation shows a result of 2.2 mFμg~(-1)for Ni@Pd/N,S-rGO,1.9 mFμg~(-1)for Cu@Pd/N,S-rGO,and 1.5 mFμg~(-1)for Co@Pd/N,S-rGO.