Preparation Of Phenol Ceria / Nano-graphite Composite Cathode And Degradation

When the electrochemical oxidation is used to remove of organic contaminants, thecathodic hydrogen evolution reaction will be restrained and the degradating efficiencyof organics can be increased if appropriate of cathode, where H2O2and free radicals canbe produced, is used. And energy consume for the electrochemical reaction will be cutdown. In this thesis, nanographite (Nano-G) was used as a conductive material andCeOx/nano-G and Pd/CeOx/nano-G cathode were prepared. The removal efficiency ofphenol and its mechnism by the electrochemical oxidation in a diaphragm cell with theRuO2/Ti anode were investigated.CeOx/nano-G composite were got by chemical precipitation method, and thepreparation conditions were optimized. The morphology and structure of the compositematerials were characterised by means of SEM、XRD、Raman and XPS. The resultsshowed that the particles of Cerium oxide were dispersed uniformly at the nanographitesheet surface with average size of10nm. And the state of Cerium in cerium oxides was+4and+3.Pd/CeOx/nano-G composite were got by formaldehyde reduction of PdCl2in thesolution of CeOx/nano-G composite. The morphology and structure of the compositewere analyzed by means of SEM, XRD and XPS. The results showed that pallaiumdispersed uniformly at the nano-G sheet surface with average size of8nm, and pallaiumexisted in the form of the elementary substance.CeOx/nanographite and Pd/CeOx/nanographite composite cathodes were preparedby using PTFE as a binder. The oxygen reduction on the cathode was studied. And theeffects of the current density, the concentration of electrolyte, the distances between theelectrodes and the electrolysis time on the degradation of phenol were investigated. Theresults indicated that the concentration of hydrogen peroxide and hydroxyl radical weregenerated by CeOx/nanographite and Pd/CeOx/nanographite cathodes were higher than that of Nano-G electrode, the hydroxyl radicals played a major role in the degradationof phenol. When the electrolyte concentration was0.1mol/L, the distance between ofthe electrodes was4cm, the initial pH value was7and the current density was39mA/cm2, the degradation rate of phenol with the above two types of compositecathodes were reached93.6%and99.6%, respectively, under120min’s electrolysis.