Electrocatalytic Reduction Of Furfural And Preparation On Modified TiO₂Thin Films

Among the numerous semiconductor materials, TiO2have attracted considerable research interest because of its strong redox selectivity, chemical-stability, no secondary pollution, as well as its electrical properties of well character. Ti/La2O3-nanoTiO2thin film electrode or Ti/Pr2O3-nanoTiO2thin film electrode were dip-coated on titania substrates from a controlled sol-gel solution using titanium alkoxide and sodium dodecylbenzene sulfonate (SDBS) as precursor and acetylacetone (AcAc) as suppressant, respectively. Nano-TiO2film electrodes were characterized by scanning electron microscope (SEM), X-ray diffractometry (XRD) and X-ray photoelectron spectroscopy (XPS). The electrocatalytic properties of nano-TiO2film electrode towards the electrocatalytic reduction of furfural to furfural alcohol were evaluated by CV and galvanostatic electrolysis experiments. The main research results are as follows:1Investigated in the TiO2film electrode preparation, the impact of surfactant on the catalytic activity of TiO2thin film electrode. In order to optimize the dispersion and wetting the surface of nanoTiO2particles, the effects of different types and amount of surface modifier added to the surface tension of the titanium fluid system. Investigated three surfactants are as follows:sodium dodecyl sulfate (SDS), sodium dodecyl benzene sulfonate (SDBS) and sodium hexametaphosphate (SHMP). CV test results showed that:electro-catalytic activity of SDBS higher than the other two surface modifier. Meanwhile explores the impact of SDBS content on catalytic efficiency of electrical TiO2film electrode. When the mass Percentage of SDBS/precursor was1%, the electro-catalytic activity of TiO2thin film electrodes after450℃heat treatment was the highest, which has the surface smooth, uniform particle distribution.2Under the optimized conditions, lanthanum nitrate hexahydrate(La(NO3)3·6H2O) as lanthanum source or praseodymium nitrate hexahydrate(Pr(NO3)3·H2O) as lanthanum source, the successful modification of the TiO2film electrode doped La or Pr. TiO2film electrodes with different doping (Ti/La2O3-nanoTiO2film electrode and Ti/Pr2O3-nanoTiO2film electrode) was prepared. The results showed that:in1mol/L sulfuric acid solution CV chart analysis was, when mole ratio of La/Ti was0.5%, Ti/La2O3-nanoTiO2prepared thin-film electrode activity was4.0times higher than the blank Ti/TiO2electrode. When the optimum molar ratio of Pr/Ti molar ratio was0.3%, Ti/Pr2O3-nanoTiO2film electrode prepared highest activity was3.5times higher than the blank Ti/TiO2electrode.3Impedance of rare La, Pr doping on nanoTiO2film electrode surface becomes smaller, this morphology of Re-doped TiO2film electrode increases the surface area of the electrode. XRD analysis, the wide peak of doped rare earth elements are incorporated into the lattice by the nanoTiO2lattice distortion and expansion, or the formation of surface oxide coatings on nanoTiO2surface. XPS showed that the surface of the rare earth element in the form of trivalent, and doped to the TiO2lattice, while increasing particle surface hydroxyl oxygen, a large number of adsorbed oxygen at the same time. A large increase in the surface hydroxyl groups can be promote the adsorption of organic matter adsorbed on the electrode surface simultaneously, improve the efficiency of the chemical reaction.4Using Ti/La203-nanoTi02film electrode (La/Ti=0.005) to study the electrical properties and mechanism of the catalytic reduction in furfural DMF organic solution. The results showed that:Ti/La2O3-nanoTiO2thin-film electrode in DMF solution containning furfural, peak current density was48mA·cm-2, the current efficiency can reach92%, the yield of alcohol reached90%, electro-catalytic activity is about3.5times than blank Ti/nanoTiO2film electrode.5Using Ti/Pr2O3-nanoTiO2film electrode (Pr/Ti=0.003) to study the electrical properties of the catalytic reduction in furfural DMF organic solution. The results showed that:Ti/Pr2O3-nanoTiO2thin-film electrode in DMF solution containning furfural, peak current density was42mA·cm-2, the current efficiency can reach90%, the yield of alcohol reached85%, electro-catalytic activity is3.1times higher than blank Ti/nanoTiO2film electrode.