Preparation Of Carbon Nanotobues Composite Materials And Their Properties On Electro-Oxidation Of P-Methoxytoluene

Anisaldehyde is a kind of significant chemical, with widely applications in the fields of perfume compositions, food, pharmaceutical drugs, cosmetic and electrodeposite. So it is very worthy to study the synthesis method of anisaldehyde. Presently, graphite electrode is the main working anodic electrode material for direct electro-synthesis of anisaldehyde. Though it’s cheap, its selectivity and current efficiency are low and anisaldehyde is easy to be further oxidized to the carboxylic acid. A few researchers use Pt electrode as working electrode for electro-synthesis of anisaldehyde, but it is expensive and easy passivated. So it is very important to improve the properties of electrode materials for electro-synthesis of anisaldehyde. In this paper, we used carbon nanotubes (CNTs) which have excellent properties as carrier, and the metallic oxide/CNTs composite were prepared, then their electro-oxidation properties of p-methoxytoluene had been studied.The CeO2/CNTs composite nano-materials were prepared by coprecipitation-temperature programme method, and characterized by the fourier transform infrared Spectrometer (FTIR), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM) and thermogravimetry analysis (TG). Then the electro-oxidation behaviours of p-methoxytoluene in different conditions were studied by cyclic voltammetry (CV). The experiment results showed that the optimum conditions of preparing CeO2/CNTs were that the calcination temperature was 550 ℃, ethanol and distilled water (1:1) mixed solutions were used as solvent and the CeO2 percentage was 20%. The diameter of CeO2 nanotubes particle was between 5 nm and 15nm. The current density of the electro-oxidation of p-methoxytoluene on CeO2/CNTs electrode could up to 6mA.cm-2, which was 1.5 times than that of CNTs modified by carboxyl.Then the MnO2/CNTs composite nano-materials were prepared by microwave and hydrothermal method, respectively, and were characterized by XRD, TEM and TG. The experiment results showed that the diameter and length of MnO2 nanorods prepared by hydrothermal method was about 19nm and between 20nm and 75nm, respectively. And the diameter of MnO2 nanorods prepared by microwave method was about 15nm and the length was between 30nm and 100nm. The current density of the electro-oxidation of p-methoxytoluene on MnO2/CNTs electrode prepared by hydrothermal method could up to 9.8mA.cm-2, which were a little higher than that of CeO2/CNTs electrode prepared by microwave method,and 3 times than that of CNTs modified by carboxyl.At last, the Pt/CNTs nanotubes materials were prepared by microwave method to reduce chloroplatinic acid with ethylene glycol used as reduction.The experiment results showed that the diameter of Pt/CNTs increased with the increasing of percentage of Pt. The 4.8%Pt/CNTs has the smallest diameter. The current density of the electro-oxidation of p-methoxytoluene on 4.8%Pt/CNTs electrode prepared by hydrothermal method could up to 8.3mA.cm-2.