Preparation And Application Of Transition Metal Sulfide Catalyst Materials

At present,the increasingly severe energy crisis and environmental pollution have seriously affected the sustainable development of society.Therefore,there is an urgent need to look for clean and renewable energy and develop efficient and environmentally friendly energy storage and conversion technologies to alleviate this phenomenon.Solar cells and electrochemical processes are important forms of energy storage and conversion.Electrode materials and electrocatalysts play an important role.Because of its controllable stoichiometric ratio,unique crystal structure,and rich redox sites,transition metal sulfides have been widely used in electrode materials and photocatalyst materials,and have become a hot spot in recent years.In this paper,by designing a new type of transition metal sulfide,its electrochemical performance as an electrode material and electrocatalyst was studied.First,the transition metal sulfide and graphene are effectively compounded,combining the unique catalytic performance of the sulfide and the excellent conductive properties of graphene to obtain a more excellent material,which is used as a counter electrode in dye-sensitized solar cells In the second,the preparation of bimetallic sulfide,due to the synergy of bimetallic,so that it has more excellent conductivity and electrochemical activity,we further explored its performance in electrocatalysis.The specific research contents are as follows:?1?Ni S/GO composite films were synthesized on FTO conductive glass by wire printing and chemical bath deposition.This preparation method saves time and is simple to operate.Firstly,the graphere was separated into single or fewer layers by ball grinding,and then prepared into a paste.The graphene film was printed on the conductive surface of FTO.Then nickel sulfide was synthesized on the surface of graphene by chemical bath deposition and nickel sulfide/graphene composite films were obtained.Nickel sulfide is attached to surface of graphene in a network structure.The undulating structure of the graphene film provides a larger specific surface area for the growth of nickel sulfide.This morphology effectively improves the diffusion capacity of electrolytes and increases the active sites of the reaction.The cyclic curve test shows that the composite electrode has a low current density,and the impedance spectrogram can prove that the composite film has a low transmission impedance,which is conducive to the rapid transmission between electrolytes.By adjusting the time of chemical bath deposition,the composite electrode with the best catalytic performance was obtained.When deposited for 8 minutes,the conversion efficiency of dye-sensitized solar energy based on nickel sulfide/graphene was 4.92%,which was similar to that of platinum electrode.The composite film combines the advantages of both nickel sulfide and graphene,and has excellent catalytic performance and electrical conductivity.Applied as a counter electrode material in DSSC,it can effectively improve its photoelectric conversion efficiency.?2?Bimetal doped Ni Co₂S₄nanosheets were successfully grown on the surface of nickel foam by a simple microwave-sulfurization method.In this experiment,Ni Co₂S₄grows vertically on a nickel foam substrate and can be used as a self-supporting catalytic material without additional binder,increasing its conductivity and increasing the number of reaction sites.At the same time,the Ni Co₂S₄nano-flower structure provides a larger specific surface area and exposes more active sites.Compared with metal oxides and single metal sulfides,bimetallic sulfides exhibit more excellent catalytic activity and higher electrical conductivity,and their electrochemical performance is also significantly improved.In alkaline electrolyte,OER has a 328m V overpotential at a current density of 50m A cm^-2and a Tafel slope of 80m V dec^-1.Ni Co₂S₄is expected to be a potential substitute for noble metal catalytic materials due to its excellent bifunctional electrocatalytic properties.