Preparation Of Titanium Dioxide Electrode And Study On Photoelectrocatalytic Decolorization Of Textile Dyeing Wastewater

Based on the traditional photocatalytic reaction,the photocatalytic technology has introduced the applied voltage,which is environmentally friendly,non-selective and strong in degradation.In recent years,it has been applied to the treatment and environmental improvement of textile dying wastewater.The selection of photoelectrode material is very important in photocatalytic system.TiO₂,as a traditional photocatalytic material,has unique ultraviolet light absorption,photoelectric conversion and photocatalytic performance,which has a wide range of application value and application prospect in the field of sewage treatment.However,TiO₂ has a large bandgap width（3.2eV）,which can only effectively absorb 5%of UV light from sunlight,and the utilization rate of light energy is low.Moreover,TiO₂ has a high photoelectron-hole recombination rate,which greatly limits the utilization of its catalytic performance.Therefore,improving the catalytic performance of TiO₂ through doping modification is the focus of the following research work.In this paper,the photocatalytic,electro-catalytic and photocatalytic decolorization properties of the prepared photoelectrode were systematically analyzed by preparing photoelectrode with modified TiO₂ material and applying it in the photoelectrocatalytic device.First,the TiO₂ NTA photoelectrode was prepared by anodization,and PPy was deposited in the nanotubes by electrochemical deposition to accompolish the modification.The prepared photoanode was characterized by SEM,XRD,Raman,UV-vis,and photoelectrochemical testing methods.The TiO₂ NTA photoelectrode was characterized and analyzed.The results demonstrated that the nanotubes on Ti O₂ NTA have uniform openings;After electrochemical deposition,there are sediments attached to the wall and surface of the nanotubes.Besides,the characteristic peak of PPy and the vibration peak of pyrrole ring were detected,indicating that PPy formed deposition in TiO₂ NTA.The light absorption capacity of PPy@TiO₂ NTA photoelectrode in the ultraviolet region was improved.Then,the catalytic decolorization performance of PPy@TiO₂ NTA photoelectrode was investigated through photocatalytic decolorization of methylene blue dye solution by photocatalytic,electric and photoelectric methods The results showed that,compared with the undoped TiO₂ NTA electrode,PPy@TiO₂ NTA photoelectrode showed more efficient decolorization efficiency in the catalytic experiments of the three systems,confirming that doping of PPy could improve the catalytic performance of TiO₂ NTA.The p-n junction was formed after p-type semiconductor PPy doping with n-type semiconductor TiO₂ NTA,which can accelerate the separation of electron-hole pairs,and it also promotes the production of active groups.In addition,it is worth noting that in the results of the photocatalytic decolorization experiment,the photocatalytic decolorization efficiency of the PPy@Ti O₂ NTA and TiO₂ NTA photoelectrodes is higher than the sum of the photocatalytic decolorization efficiency and the electrocatalytic decolorization efficiency,proving the existence of photoelectric synergy.In addition to the photoelectrode with a metal carrier,we constructed a ternary photoelectrode composed of reduced graphene oxide（rGO）doped nano-TiO₂ composite filter paper as a photoelectrode.SEM,XRD,EDS,UV-vis were used to characterize the prepared photoelectrode.The results showed that oxygen and carbon elements were evenly distributed on the filter paper film,and the absorption of rGT@FP photoelectrode in the visible light region was enhanced.The instantaneous photocurrent is about 3.5 times higher than that of the undoped blank photoelectrode TiO₂@FP.The photocatalytic decolorization performance of rGT/FP photoelectrode was characterized by catalytic decolorization of simulated wastewater inmethylene blue.Compared with the undoped TiO₂/FP photoelectrode,the photochromic,electrical and photoelectric decolorization efficiency of the rGT/FP photoelectrode on MB dye solution was higher.This is mainly because the doping of rGO accelerates the separation of photogenerated electron hole pairs and promotes the improvement of catalytic efficiency.Moreover,due to the photoelectric synergistic effect,the decolorization efficiency of photocatalysis is higher than that of photocatalysis and electrocatalysis combined.