Controllable Structure And Catalytic Properties Of Monodisperse Cobalt (nickel)-based Sulfur (phosphorus) Compounds And Composite Materials

Dye-sensitized solar cells?DSSCs?are a promising alternative to traditional silicon-based solar cells due to their relatively high power conversion efficiency,cost-effectiveness,and environmentally friendly manufacturing processes.The counter electrode is an important component of DSSCs.Platinum?Pt?is considered to be the most ideal counter electrode material for DSSCs due to its superior electrocatalytic activity.However,Pt limits its application due to its high price and scarce reserves.Therefore,under the premise of not affecting the electrochemical performance,look for alternative materials with low cost and abundant reserves to reduce the overall manufacturing cost.In this paper,low-cost monodisperse cobalt?nickel?-based sulfur?phosphorus?compounds and composites were prepared by simple synthesis methods,and their electrochemical properties as counter electrode materials of DSSCs were investigated.The main research contents are as follows:Co₉S₈ nanocrystals with cobalt oleate as the metal source and a mixed solution of sulfur powder and oleylamine as the sulfur source were prepared by simple hot injection method.The optimum temperature?300 ^oC?of the reaction was determined by adjusting the reaction temperature.Then,Graphite Oxide?GO?was added to the reaction system at an optimum temperature to prepare a Co₉S₈/RGO composite.The optimal ratio of Co₉S₈ nanocrystals to reduced graphene oxide?RGO?was determined by adjusting the amount of GO added.After photocurrent-voltage test,the results show that when the content of RGO in the composite is 44.4%,that is,Co₉S₈/RGO-44.4%,it shows superior photoelectric conversion efficiency?7.31%?,which is comparable to 7.72%of platinum-based DSSCs.The superior photoelectric conversion efficiency is derived from the synergy between Co₉S₈ nanocrystals and RGO.In addition,the Co9S8/RGO-44.4%composite exhibits good electrochemical stability in an electrolyte containing I₃^-/I^-.Therefore,Co₉S₈/RGO-44.4%composites are expected to be a replacement for platinum-based materials.A small-sized,monodisperse Ni₁₂P₅ nanocrystal was prepared in situ on the surface of RGO by a simple one-pot method to form a Ni₁₂P₅/RGO composite.The optimal ratio of Ni₁₂P₅ nanocrystals to RGO was determined by adjusting the content of RGO in the composite.Photocurrent-voltage tests were carried out based on DSSCs assembled from Ni₁₂P₅/RGO composites.The results show that the addition of 30mg GO to the reaction system,ie Ni₁₂P₅/RGO-35,exhibits excellent photoelectric conversion efficiency?8.19%?and can be platinum-based.?8.52%?DSSCs are comparable.The performance of the Ni₁₂P₅/RGO-35 composite battery exhibits excellent battery performance mainly due to the synergy between the two.In addition,the Ni₁₂P₅/RGO-35 composite also showed good electrochemical stability in the I₃^-/I^-electrolyte.Therefore,the Ni₁₂P₅/RGO-35 composite has the potential to replace the precious metal platinum.