| Owing to the pollution caused by traditional fossil energy and the growing problem of energy crisis,solving the environmental problem and developing the renewable clean energy have been the hot topic.Environmental problems such as water pollution can be solved via anatase TiO2 for its high photocatalytic property in degradation the organic contaminants.However,it shows poor selectivity in the process of photocatalysis.Hence,it is strongly essential through improving the selectivity by controlling the facet of anatase for decreasing the dispersivity of surface atomic structure and electronic structure of photocatalyst.The research contents and results are as follows:Firstly,the anatase TiO2 with exposed(001)facets are obtained on the basis of hydrothermal method,NaF and HCl adopted as morphology used to successful prepares anatase with the shape of truncated bipyramids.It is obviously that both of(001)facets’proportion and size of the TiO2 particles are increasing with increasing of HF concentration until 111 mM under 200 ℃ temperature and 14 h reaction time.Than keeping HF concentration at 74 mM,with extending of reaction time,the(001)facets’ proportion is unchanged while the size is increasing.Secondly,NaF which was used to F resource replace the HF to prepare the Ti02 with exposed(001)facets.The result shows that formation of TiO2 with exposed of(001)facets is the co-effect of F’ ions and H+ ions.Thirdly,we separately study the influence of F-ions and H+ ions concentration on the shape controlling through varying the concentration of NaF and HCl alone.The results show both H+ ions and F-ions effect the synthesis of truncated anatase bipyramids.And the optimal ratio of F-ions and H+ ions concentration is 1:20 for shape controlling.Under this condition,the smallest and the largest percentage of(001)facets particles we can get.Meanwhile,the photocatalytic properties result show that the smaller the crystal size and the higher the truncation degree,the better photocatalytic properties of TiO2 crystals.DMFCs have been a hotspot in new energy research because of its low pollution,rich source and portability recently.Platinum-based catalysts as anode catalysts are most widely utilized in DMFCs,however,the large scale commercial application of DMFCs are limited to current high expenditure and low efficiency.Platinum nanoparticles/indium tin oxide nanocomposites are hoped to improve the catalytic efficiency and stability.The research contents and results are as follows:First,uniform ITO nanoparticles were prepared via chemical coprecipitation method.To obtain the good crystalline and well disperse ITO nanoparticles,we used PEG as dispersing agent and regulate sintering temperature to investigate.And we found that the best ITO particles were gotten with 800 ℃ sintering temperature and 2.5 per thousand PEG.Second,in order to further improve the catalytic activity of the Pt-based catalyst,we synthesized PtNPs/ITO nanocomposites with self-made ITO nanoparticles as substrate support the Pt nanostructures.The TEM results exhibit that the Pt nanoparticles are well-dispersed on the surface of ITO nanopowders.In the further electrochemical evaluations,better electrocatalytic activity and stability towards the electro-oxidation of methanol belong to the catalyst.And we further study the influence of different reaction parameters on catalytic properties of composites.It indicated that the composites synthesized with 2 mM K2PtCl4 and 6 hours exhibit the best electrocatalytic activity towards the methanol.All of these verifying ITO nanoparticles the potential use as new and well substrates materials for loading noble metal. |
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