Research On N-doped Carbon Nanotubes/Molybdenum Compounds Nanocomposites As Counter Electrodes

With the progress and development of human society,energy has become an indispensable power whose depletion begun to threaten the survival of mankind.Meanwhile,the excessive utilizations of traditional energy sources have led to lots of environmental issues,such as greenhouse effect,ozone hole and haze.Solar energy,which is a kind of clean and renewable energy,has received widespread attention for the purpose of alternating fossil fuels and improving the environment pollution.The method of using solar energy is mainly depending on transforming solar energy into electric energy which is stored in solar cells via photovoltaic effect.A novel solar cell,which called dye-sensitized solar cell?DSSC?,has the prominent position in the multitudinous solar cell market.DSSC has been equipped with many advantages,including low cost,easy production process and light weight.Pt is the universal electrode of high performance DSSC,which will be depleted in the charging and discharging processes of battery.Hence,we have done much effort to substitute Pt for the anode of DSSC in this work.In this project,MoO₃ nanowires were prepared by hydrothermal method,and then stirred in the ice water bath,coated with polyaniline and polypyrrole respectively.From polyaniline coated material,Local-ordering MoO₂ nanostructures within porous N-doped carbon nanotubes?MoO₂/NCNTs?nanocomposites could be obtained by situ solid reaction,which were conducted in argon atmosphere at a tube furnace.While polypyrrole coated material was conducted in ammonia gas atmosphere,and Local-ordering MoN nanostructures within porous N-doped carbon nanotubes MoN/NCNTs nanocomposites were obtained.The two kinds of nanocomposites were characterized by transmission electron microscopy?TEM?,X-ray diffraction?XRD?,X-ray photoelectron spectroscopy?XPS?.It could be found that the inners of MoO₂/NCNTs nanocomposites were crystal MoO₂ and divided into many separated nanoribbons with a length of 200 nm and a thickness of 15 nm,forming local-ordering porous structures.The spaces between the adjacent nanoribbons were ranging from 1 to 3 nm.The MoN/NCNTs nanocomposites have similar morphologies with MoO₂/NCNTs that have crystal MoN inners and amorphous N-doped carbon nanotubes externals.Compared with MoO₂/NCNTs nanocomposites,the thicknesses of external carbon nanotubes of MoN/NCNTs nanocomposites were thinner.The MoN/NCNTs nanocomposites,the MoO₂/NCNTs nanocomposites and the Pt were applied as anodes for DSSC.From the performance testing results of electrochemical workstation,the photoelectric conversion efficiencies of MoO₂/NCNTs nanocomposites approximated to that of Pt.And the MoN/NCNTs nanocomposites also posses favorable photoelectric conversion efficiencies for DSSC.On the basis of these results,the MoN/NCNTs nanocomposites,the MoO₂/NCNTs nanocomposites have great potential as anodes for DSSC.