Inorganic Nanaparticles/Mesoporous Carbon Composites: Preparation And Their Electrochemical Application

Mesoporous carbon materials possess3D porous structure and high surface area, andattract much attention for their application as catalyst support in electrochemistry. The highsurface area of mesoporous carbon is favorable for the exposure of active sites for thedeposition of inorganic nanoparticles. The mesoporous structure provides a more favorablepath for electrolyte penetration and transportation, while the high surface area and the largenumber of mesopores of the mesoporous carbon allow for the obtainment of high metaldispersion. The mesopores also serve as barriers to suppress agglomeration of particles andcan be used as confined space for the growth of nanoparticles. Compared with the bulkmaterials, nanoscale particles exhibit many different properties due to the volume effect. Themesoporous carbon and nanoparticles exhibit different physical and chemical properties,which can compensate each other. Therefore, the combination of porous carbon andnanoparticles into hierarchical structure is a promising method to integrate theirdistinguishing properties together.In the introduction, the methods for synthesis of mesoporous carbon and commonmethods for the functionalization of nanoporous carbons were summarized. The applicationof mesoporous carbon in electrocatalysis and catalyst support was emphasized especially. Theintroduction of noble metal nanoparticles further extends the application of mesoporouscarbon and provides new features such as catalytic and electrochemical activity. Many novelmethodologies used to introduce Pt nanoparticles on mesoporous carbon were discussed in theintroduction. In this dissertation, mesoporous carbons were used as catalysts support fordeposition of inorganic nanoparticles. Glucose, hydroperoxide, hydrazine, and methanol wereselected as marked molecules to evaluate the electrochemical activity of inorganicnanoparticles/mesoporous carbon composites. This dissertation mainly consists of thefollowing several aspects:(1) A simple and facile synthetic method to incorporate cupper sulfide (Cu2S)nanoparticles inside the mesopores of ordered mesoporous carbons (OMCs) is reported. TheCu2S/OMCs nanocomposite was characterized by transmission electron microscopy (TEM),X-ray diffraction (XRD), X-ray Photoelectron Spectroscopy (XPS), and nitrogenadsorption-desorption. The results show that the incorporation of Cu2S nanoparticles insidethe pores of OMCs does not change the highly ordered two-dimensional hexagonalmesostructure of OMCs matrix. Nonenzymatic amperometric sensor of hydrogen peroxidebased on the Cu2S/OMCs nanocomposite modified glassy carbon (GC) electrode is developed. Compared with the pristine OMCs modified electrode, the Cu2S/OMCs modified electrodedisplays high electrocatalytic activity towards hydrogen peroxide and gives linear range from1to3030μM (R=0.9986). The sensor also exhibits good ability of anti-interference toelectroactive molecules. The combination the unique properties of Cu2S nanoparticles and theordered mesostructure of OMCs matrix guarantee the excellent electrocatalysis for hydrogenperoxide. The good analytical performance and low cost make Cu2S/OMC nanocompositepromising for the development of effective sensor for hydrogen peroxide.(2) A facile and fast microwave irradiation method was developed to prepare PtPdbimetallic alloy nanoparticles on onion-like mesoporous carbon vesicle (MCV). With MCVact as a template, its high surface area favors the formation of nanosized PtPd particles. ThePtPd/MCV nanocomposite was characterized by transmission TEM, scanning electronmicrographs (SEM), XRD, and XPS. A nonenzymatic amperometric sensor of glucose basedon the PtPd/MCV modified GC electrode is developed. Compared with the Pt/MCVnanocomposite, the PtPd/MCV modified electrode displays enhanced current responsetowards glucose and gives linear range from1.5to12mM. The particular lamellar structureof the MCV results in favorable transport passage for glucose. The modified electrodeachieves95%of the steady-current within3s. This nonenzymatic glucose sensor also exhibitsgood ability of anti-interference to electroactive molecules. The fast response and facilepreparation method make PtPd/MCV nanocomposite promising for the development ofenzyme-free sensor for glucose.(3) Hollow carbon spheres (HCSs) are prepared using poly(ionic liquid)(PIL) as acarbon precursor and monodisperse silica particles as a template for the first time. ThePILs can be used to overcome the fluidity of IL. The IL form a uniform polymer coatingon the template surface after polymerization. Carbonization of the coating and thesubsequent removal of the template produces porous carbon spheres with a hollowstructure. The HCSs possess a high surface area, good conductivity, and porosity suitablefor mass transport, and they can be used as a support for Pt electrocatalysts. Ptnanoparticles with an average size of2.8nm are homogeneously distributed onto theHCSs. The high surface area and unique structure facilitates the fine dispersion of Ptnanoparticles. The obtained Pt/HCSs exhibit significant catalytic activity for the oxidationof methanol.(4) Poly(ionic liquid)(PIL) coated OMCs were prepared by in situ polymerization of3-ethyl-1-vinylimidazolium tetrafluoroborate ([VEIM]BF4) monomer on OMCs matrix. PILon the surface of OMCs can provide sufficient binding sites to anchor the precursors of metalion. PIL/OMCs were employed as support materials for the deposition of ultra-fine Ptnanoparticles via the self-assembly between the negative Pt precursor and positively chargedfunctional groups of PIL-functionalized OMCs. The combination the unique properties of each component endows Pt/PIL/OMCs as a good electrode material. Compared with thePt/OMCs nanocomposites, the Pt/PIL/OMCs modified electrode displays high electrocatalyticactivity towards probe molecules. The improved activity makes Pt/PIL/OMCsnanocomposites promising for being developed as a good electrode material inelectrochemical analysis.(6) A facile template-free strategy was used for synthesis of rectangular mesoporouscarbon nanorods (meso-CNRs). Rectangular crystalline nanorods of nickeldimethylglyoximate complex are firstly formed in water without template, and subsequentcarbonization and selective etching give rise to rectangular meso-CNRs. The rectangularmeso-CNRs possess a large surface area, good conductivity, and high porosity for masstransport, and they can be used as a support for Pt electrocatalysts. The high surface area andporous structure of meso-CNRs facilitates the fine dispersion of Pt nanoparticles. Ptnanoparticles with an average size of3.1nm are distributed onto the meso-CNRs. Theobtained Pt/meso-CNRs exhibit significant catalytic activity towards the oxidation ofmethanol. The superior performance makes rectangular meso-CNRs promising for beingdeveloped as a good support material.