| platinum nanomaterial is an effective catalysts widely used in the field of catalyticactivity in the fuel cell and petrochemical industrial sectors. However, the theoreticalstudies shown platinum nanomaterial with high index facets have kink atoms of low-indexplanes such as {100},{111} have higher catalytic activity. Therefore, the preparation ofcatalyst with high-index planes and defect sites is the most effective way to improvecatalytic activity and stability.This paper consists of three parts:1. Preparation of platinum nanocrystals and the study on electrocatalytic activity.Platinum has been widely used in catalysis and fuel cell technologies, because it has theability to manipulate oxidation and reduction reactions. In addition to nanocrystal size, itsshape and morphology can also regulate catalytic and electrocatalytic properties. There arealready a large number of synthetic routes to control the synthesis of platinum nanocrystalsthat have well shape to improve their catalytic performance and selectivity, such aspolyhedron, e.g., cubic, octahedral, tetrahedral, and some overgrowth structures of whichshapes can be synthesized in high yield. These nanocrystals catalyst has high activity.Platinum nanocrystals were synthesized and adsorbed on carbon nanotubes and thenheat treated. Effects of heat treatment on activity and stability was studied. The catalystswere characterized by X-ray photoelectron spectroscopy, transmission electron microscopyand high-resolution transmission electron microscopy. Here, we put the synthetic materialon the glassy carbon electrode surface, and studied the effects of temperature and gasatmosphere on its electrocatalytic oxidation-reduction reaction activity.2. Study on distribution of oxygen reduction active sites of nitrogen doped grapheneGraphene has been found to have a high mechanical rigidity, strength and elasticity andthermal conductivity of the two-dimensiona（l2D）atomic crystal material. It is an ultra-thin,conductive and transparent, and has a great potential in the field of electronic andopto-device research areas. Nowadays, methods for preparing graphene is varied, but grapheme oxide (GO) reduction method is the most frequently used. Finally, these methodsobtained a mixture solution of graphene, which have different layers and sizes. They alsohave significant impacts on the gas sensor, electrochemical biosensor and constructedelectronics. GO can be seen the derivatives of graphene, that is, the surface of graphenefragments derived some oxygen-containing functional group such as a hydroxyl group, anepoxy group, a carboxyl group derived from the edge.Here, thin-layer GO sheets were obtained after dialysis, and then dip-coated on electrodesurface. Nitrogen-doped material was obtained after hydrazine hydrate reduction. After theelectrochemical deposition of ZnO, we use TEM and HRTEM to observe nitrogen-dopedsites and distribution of ZnO deposited sites. Finally, we can inferred the active sitedistribution of oxygen reduction active sites of nitrogen-doped graphene.3. Anodic stripping voltammetry measurements of heavy metal content in waterHeavy metal pollution (e.g. Pb, Cd) is wide spread. Hg electrode is generally used inelectrochemistry. However, alternative electrode is needed because Hg is toxic. Bielectrode is selected in this experiment, which is used as "green" sensor material, becausethat it has a good analytical performance and environmental benefit. Bismuth film can beobtained by this method that Bi3+is added directly to the sample solution in the analysisand the ion is to be deposited together with Bi3+on the electrode surface during analysis.The advantage of this method is simple and easy to operate. It also has very highsensitivity and low cost. Furthermore, it has a very wide range of practical applications. |
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