Decomposition of Gaseous Isopropanol by UV/TiO2 Process with Applying Bias Potential in a Polymer Electrolyte Cell

Abstract

Photocatalytic (PC) oxidation processes using semiconductor particles have attracted numerous researches as a promising and effective technology to degrade refractory pollutants in the field of water and air treatment. However, the effectiveness of PC processes is critically restricted by the rapid recombination of photogenerated electron-hole pairs [Ku et al., 2010]. The photoelectrocatalytic (PEC) process is considered as a promising modified PC process by applying bias potential in the photoanode [Ku et al., 2006]. The potential electric field drives the photogenerated electrons and holes in opposing directions and then prevents the recombination of electron and hole. The PEC process is wide utilized in the environmental treatment; however, the application of PEC decomposition of organics is extremely restricted in gas phase due to limitation of aqueous electrolyte [Georgieva et al., 2010]. A proton exchange membrane (PEM) fuel cell using Nafion as the solid electrolyte is commonly applied to generate electricity by oxidizing hydrogen and reducing oxygen, respectively. Photoelectrocatalytic decomposition of gaseous isopropanol (IPA) was investigated by applying bias potential in a polymer electrolyte cell. The Nafion membrane, a proton exchange medium, served as the solid electrolyte in the polymer electrolyte cell. The TiO2 particles were well dispersed on the surface of stainless steel electrode through the dip-coating process as the photoanode and attached one face of the membrane. The cathode made by a plain stainless steel was attached to the opposite face of photoanode. The effect of applied bias and the role of water molecules on the PEC reaction were discussed in electrocatalytic (EC), PC and PEC reaction.