Study On The Preparation Of Sb Doped SnO₂ Photoelectrode And Its Photoelectrocatalytic Properties

Sb doped SnO₂ is a new photocatalyst that shows high photoefficiency andoxidation activity in the organic wastewater treatment. It has become a hotresearch area because it can decompose organic pollutants into CO₂ and H₂O ingases and liquids. Photoelectrocatalysis is a method that applied a bias potentialto take away the photoelectrons and decrease the combination of electron-holes.So the method can increase the photoefficiency evidently.In this paper, the Ti/SnO₂-Sb₂O₄ electrodes (one with addedintermediate-layers, the other without intermediate-layers) were prepared andcharactered by SEM and EDS, and charactered by XRD after degradationexperiment; the gas diffusion electrode was prepared and also charactered byXRD and SEM. The results showed that the specific surface area of both twoTi/SnO₂-Sb₂O₄ anode was large, EDS results showed that the experimentalcomposition on Sn and Sb atoms and was accordant with the nominalcomposition, the crystalline of both two Ti/SnO₂-Sb₂O₄ electrodes was rutile,the titanium or titanium oxide was not found in the surface of the Ti/SnO₂-Sb₂O₄electrode added intermediate-layer after degradation experiment; the specific surface area of gas diffusion electrode was large, the main crystalline of thiselectrode was graphite and Mn₃O₄, the materials and pores were well-distributedon the surface and inside of the electrode, it is a electrode with excellentcatalytic property and is favorable to mass transfer,diffusion and reaction ofsystem.The Ti/SnO₂-Sb₂O₄ electrode was used as the working electrode, the gasdiffusion electrode was used as the counter electrode. A 250 W UV lamp(365nm) was used as side light-source. One of the most typical and difficultlydegraded aromatic compounds-phenol was the objective substance. Compressedair was bubbled upward through the gas distributor installed at the bottom of thereactor in all experiments. Sample was taken out each 30min to analyze. Thephenol concentration was measured by a spectrophotometer; the mineralizationdegree was determined by the TOC value determined by TC analyzer.The effects of the different conditions of preparing the Ti/SnO₂-Sb₂O₄electrode on the photoelectrocatalytic property were investigated; we alsoobserved the effects of some factors such as initial pH value of solution,operated voltage,electrolyte and initial density on degradation of phenol; theremovals of phenol in different processes including adsorption, photocatalysis,electrocatalysis and photoelectrocatalysis were compared in the same condationsof operation; the effects of different anodes and different cathodes wereobserved as well. The results showed that the Ti/SnO₂-Sb₂O₄ electrode whichdoped 6% of Sb, calcined at 450℃. added intermediate-laver, coated with 15 layers, had the favourite photoelectrolytic activity. The good synergetic effectwill appear in process of photoelectrocatalytic degradation of phenol in water ifthe Ti/SnO₂-Sb₂O₄ electrode and the gas diffusion electrode were prepared underthe favourite experimental conditions of preparation.