Designed And Synthesis Of Peapod-like Cu₂S/C And Its High Efficient Application In Oxygen Evolving Reaction

Nowadays,with the rapid development of global economy,clean energy has become a hot research topic,which could replace fossil fuels in many fields.The green-friendly oxygen has attracted the attention of researchers.Electrochemical water splitting is a promising method to produce oxygen.Unfortunately,the high reaction energy barrier brings about the sluggish dynamic of oxygen evolution reaction（OER）,which severely limits the efficiency of producing oxygen.Therefore,synthesis of the highly efficient catalysts is one of the breakthrough points to produce oxygen,efficiently.Noble metal catalysts,such as Ru and Ir,are considered as the state-of-the-art electrocatalysts for oxygen evolution reaction.However,owing to the high price and scarcity,seeking highly effective and robust alternates from earth-abundant elements has been vigorously pursued.Among these alternates,Cu plays an important role in the OER process,thus Cu-based compound obtains more and more attention.It is worth mentioning that Cu-based compound,especially Cu₂S,is the high-efficiency and promising electrocatalyst for OER.It is reported that the morphology and structure of electrocatalysts greatly influence their electrocatalytic activity.Therefore,designing the novel nanostructure with especial morphology for electrocatalysts makes a positive effect on electrocatalytic activity.In this paper,we have successfully synthesized the peapod-like Cu₂S/C nanocomposite,for the first time,which is applied to oxygen evolution reaction and displays excellent electrocatalytic performance.This paper adopted the co-precipitation method to successfully synthesize the one-dimensional Cu（OH）₂ nanorod precursor,which could act as the sacrificial template to obtain the peapod-like Cu₂S/C nanocomposite.And then,the glucose molecule as cheap carbon source reacts with the one-dimensional Cu（OH）₂ nanorod precursor to produce the polymer-coated intermediate,through the hydrothermal method.Next,combined with the high-temperature solid state method,the as-obtained polymer-coated intermediate is calcined with sulfur powder to successfully synthesize the peapod-like Cu₂S/C nanocomposite.This work has employed various test techniques to characterize the the peapod-like Cu₂S/C nanocomposite,such as XRD,SEM,XPS,EDS,BET,ICP,Raman,TEM,etc.In the peapod-like structure,the Cu₂S nanoparticles with uniform size are evenly encapsulated in the graphitized carbon films,which could prevent active nanoparticles from agglomeration and exfoliation after the long-time electrochemical testing.The graphitized carbon films own porous structure,which could promote the contact between electrolyte and active material,reducing the kinetic resistance.Meanwhile,the graphitized carbon films offer the high surface area to expose more the active sites.During electrochemical measurements,the peapod-like Cu₂S/C nanocomposite displays an enhanced electrocatalytic activity with a low overpotential of 401 mV at the current density of 10 mA cm^-2 and a low Tafel slope of 52 mV dec^-1.More importantly,the as-obtained peapod-like Cu₂S/C nanocomposite could maintain stability for at least 8 h at constant potential and the current loss is negligible after 2000 cycles.Obviously,these striking performances fully demonstrate that the peapod-like Cu₂S/C nanocomposite is an efficient OER catalyst,presenting a vast potential for future development.