The Preparation And Optical Properties Study Of Low-Platinum Electrode Materials

Developing green and renewable energy resources has become an urgent priority for the world with the accelerated depletion of the earth's fossil fuels.Solar energy and bioenergy are developed and utilized,owing to their high reserves,sustainable development,and no pollution.Solar energy which is pollution free and abundant radiating all regions of the globe has been regarded as one of the perfect energy resources.It is urgent to develop cheap and efficient devices for converting light into electricity.Dye-sensitized solar cells?DSSCs?,which own the merits of low cost,simple manufacture procedure and high theoretical energy conversion efficiencies,is expected to replace traditional silicon solar cells,and become dominant in the field of solar cells in the future.A typical DSSCs consists of a photoanode,an electrolyte and a counter electrode?CE?.The main functions of the counter electrode are the collection of electrons and the catalysis of the redox species regeneration reaction.The performance of DSSCs depend on catalysis,electrical conductivity and stability of the counter electrode.Normally,platinum?Pt?is used as counter electrode because of its prominent catalytic activity,superior conductivity and high chemical stability.However,the high cost and rarity of Pt was the biggest obstacle for the large scale commercial application of DSSCs.Recently,many Pt-free materials have been tried in DSSCs with the hope to find a replacement for the Pt counter electrode material.Except solar cells,fuel cells have attracted widespread attention and research,due to its high energy conversion efficiency,no environmental pollution,and wide application.Microbial fuel cells?MFCs?,represents the newest electricity production device,using microorganisms as catalysts and bio-electrochemical reaction to generate electricity.But the traditional MFC cathode also is precious metals Pt.Therefore,this paper devotes to the development and utilization of high efficiency low Pt composite materials which will be applied to the CE of DSSCs and the cathode of single chamber MFCs.?1?The composite materials of Pt3 Ni and Mo-Pt3 Ni supported on carbon nanofibers were synthesized using high temperature oil bath method and used as novel counter electrode catalysts in DSSCs.The surface features and morphology of the composite materials were studied using X-ray diffrication?XRD?,scanning electron microscopy?SEM?,transmission electron microscope?TEM?.The performance of different CEs was studied using cyclic voltammetry?CV?,electrochemical impedance spectroscopy?EIS?,Tafel curves,and J-V curves.Results show that Mo-Pt₃Ni/CN exhibits a high catalytic activity.The DSSCs based Mo-Pt₃Ni/CN electrode obtained an excellent PCE of 9.47%,higher than of Pt?7.1%?.As a result,Mo-Pt₃Ni/CN can be a feasible material to produce substitutes for Pt in DSSCs.?2?The nanostructured nickel phosphide supported on carbon nanofibers?Ni₂P/CN?was prepared by thermal decomposition using nickel acetylacetonate Ni?acac?2 as nickel source and trioctylphosphine?TOP?as phosphorus source in an oleylamine?OAm?solution containing CNs.The Pt/CN and Pt-Ni₂P/CN were prepared by Pt particles load on CN and Ni₂P/CN using calcination method,respectively.The surface features and morphology of the composite materials were studied using XRD,SEM,and TEM.The performance of different CEs was studied using CV,EIS,Tafel curves,and J-V curves.Results show that the DSSCs device fabricated with Pt-Ni₂P/CN CE shows an excellent power conversion efficiency of 9.11%,which is about 10% increase than the DSSCs with Pt/CN electrode?8.35%?.As a result,Ni2 P supported on Pt/CN catalyst was beneficial to the catalytic performance of the counter electrode.?3?This work deals with the use of optimized loading by CeO₂ doped commercial Pt/C?Pt/C,1%CeO₂-Pt/C,3%CeO₂-Pt/C,5%CeO₂-Pt/C,10%CeO₂-Pt/C?cathode to improve the performance of single chamber MFCs.The highest output voltage?580 mV?,the maximum power density?840±24 mW/m2?,and the best ORR of catalyst were obtained by the use of 3wt% CeO₂-Pt/C cathodes in single chamber MFC.However,in EIS test,3%CeO₂-Pt/C resistance was greater value than Pt/C.The reason may be that CeO₂ exhibit good oxygen storage and catalyst,but its poor electrical conductivity.Excess CeO₂ inhibit the electrical conductivity of the electrode,which affect the production performance of MFC.