Study On Photoelectric Properties Of Sulfide Films Based On Zeolite Imidazole Framework Compounds

Zeolite imidazolide frameworks?ZIFs?process the structure advantages of inorganic zeolites and metal organic frameworks?MOFs?:regular pore structure,high specific surface area and good physicochemical stability.ZIFs sulfides enhance the conductivity of ZIFs,and the pore structure increases the specific surface area,providing a rich active site.In this paper,ZIFs were directly grown on fluorine-doped conductive glass?FTO?by dipping method,and then sulfuretted by chemical vapor deposition?CVD?method to obtained sulfide film with ZIFs skeleton structure.As a counter electrode?CE?of dye-sensitized solar cells?DSSCs?,the sulfide films exhibited excellent activity for electrocatalytic reduction of I₃^?.?1?ZIF-8 were deposited on the FTO by dipping method and then sulfuretted by CVD method to investigate the effect of skeleton structure and degree of sulfuration on electrocatalytic performance.The micropolyhedral ZnS?ZDS-500?which obtained by sulfuration at 500°C,had a large value of reduction peak current density(J_cp:3.40 mA cm^-2)in cyclic voltammetry,indicated that it had a high electrocatalytic reduction rate.As a CE of DSSC,the photoelectric conversion efficiency?PCE?was 8.20%;indicated that the high degree of vulcanization was beneficial to increase the catalytic activity.From the electrochemical impedance spectroscopy test,the charge transmission impedance of ZDS-500?Rct:45?cm²?was quite small,exhibited that it had great conductivity and was beneficial to the improvement of catalytic properties.In the process of pulsed laser deposition?PLD?,high-energy laser shatters the zeolite-like structure of ZIF-8,so that the electrochemical performance was greatly reduced.The PCE decreased from 8.20%to 5.56%,the R_ct value increased to 233?cm²,and the J_cpp value decreased to 3.00 mA cm^-2.?2?The zinc and cobalt nitrates were mixed and the ZnCo-ZIFs were deposited directly on the FTO by dipping method.Then sulfuretted at 500°C by CVD method to investigate the effect of bimetallic sulfide on electrocatalytic performance.The Zn_0.76Co_0.24S was used as a CE of DSSCs,the PCE was up to 10.02%.The J_cp(3.28 mA cm^-2)in CV test was close to Pt,indicated that it had high electrocatalytic effect and can be used as one of the substitutes for Pt.The charge transport resistance value(R_ct27?cm²)of Zn_0.76Co_0.24S was significantly lower than that of single metal sulfide ZDS-500?Rct:45?cm²?,indicated bimetallic sulfide was facilitated electron transport and had a higher conductivity,then the electrocatalytic activity can be improved.Compared with single metallic sulfides,bimetallic sulfides had synergistic effects of polymetallics,rich atomic bonding and more active sites,and their catalytic performance was more excellent.