Research On Preparation And Electrocatalytic Performance Of Molybdenum Disulfide Based Electrocatalyst

Hydrogen energy as a clean and renewable emerging energy source has attracted great attention.The electrochemical decomposition of water to produce hydrogen is considered to be one of the most promising methods for hydrogen energy production and storage in the future.At present,researchers have explored a variety of electrocatalytic and earth-rich transition metal-based compounds to improve the efficiency of water splitting,such as transition metal sulfides,transition metal phosphides,and transition metal oxides.As a typical transition metal disulfides,molybdenum disulfide(MoS2)with small free energy of hydrogen adsorption(?GH*?0.6 eV),is considered to be one of the most promising alternatives to precious metal catalysts(?GH*?0.0 eV).Pure phase MoS2 has better hydrogen evolution reaction(HER)activity,but oxygen evolution reaction(OER)performance is still limited.In this work,metal phase MoS2(1T-MoS2)obtained through the phase transition of MoS2,achieves a dual-functional catalyst with rich active sites and excellent conductivity by means of doping and coupling with other catalysis phases.The prepared bifunctional material is used as electrocatalyst in alkaline/neutral medium for efficient overall water splitting.The microscopic characteristics and electrochemical properties of material were systematic in-depth studied.The main research conclusions are as follows:(1)The Fe and Mn co-doped free-standing coral-like 1T-MoS2 electrocatalyst is prepared via one-step in-situ hydrothermal method.Fe and Mn doping can trigger HER and OER bifunctionality of MoS2-based electrocatalysts for overall water splitting.The microstructures of the samples were characterized by XRD,Raman,SEM,TEM and HRTEM.The results demonstrate that doping foreign atoms induces rich crystal defects and electronic structure variation of the free-standing coral-like 1T-MoS2,leading to outstanding HER and OER activity in alkaline media.Based on the optimized molar ratio of Fe:Mn:Mo(0.15:1:1),the as-prepared free-standing FeMn-1T-MoS2 exhibits the best HER(55.9 mV@10 mA Cm-2)and OER(280.0 mV@50 mA cm-2)performance.Further,photodepositing fewer Pt(0.3 wt.%)on FeMn-1T-MoS2 further boosts HER(34.1 mV@10 mA cm-2)and OER(220.0 mV@50 mA cm-2)performance of FeMn-1T-MoS2,and exhibits good stability in alkaline media.(2)The composite catalyst of Fe-1T-MoS2/CoxP is synthesized by a simple photo-compositing method.SEM,TEM,HRTEM,XPS,and EDS elemental analyses are also characterized to verify the loading of CoxP on Fe-1T-MoS2.Electrocatalytic measurements show that Fe-1T-MoS2/CoxP composite material can provide more reactive active sites and larger electrochemically active area,lower electron transmission resistance and good water splitting stability,thereby achieving high-performance of water decomposition in a wide pH(pH=7.0-14.0)medium.Under optimized photo-combination time of 60 minutes,the Fe-1T-MoS2/CoxP-60 shows the best HER(40.7 mV@10 mA cm-2)and OER(300.0 mV@100 mA cm-2)performance in 1.0 M PBS and excellent HER(43.8 mV@10 mA cm-2)and OER(270.0 mV@150 mA cm-2)performance in 1.0 M KOH media.