Preparation And Photoelectrocatalytic Activity Of Titania-based Photoanode Coated On Foam Nickel

The porous TiO₂film electrode coated foam nickel （PTFN） was successfullyprepared by a hard-template method with using activated carbon, foam nickel as apore-forming agent and a substrate in this paper. The photoelectrocatalytic degradationof methylene blue（MB） by the porous TiO₂film electrode coated foam nickel under UVirradiation light was investigated in a homemade photoelectrocatalytic reactor whichused the thin film electrode as working electrode, copper electrode as counter electrode.the main influencing factors, such as the number of coating, activated carbon doping,anode bias voltage, ventilation rate and initial concentration of MB, which effect of thephotoelectrocatalytic degradation of MB was discussed. The results show that thephotoelectrocatalytic degradation rate of MB was greatly enhanced by the synergeticeffect of photoelctrocatalysis and adding activated carbon as a pore-forming agent.Additionally, there exits an optimum photoelectrocatalytic degradation conditions. whencoating thin film four times and under3V of bias voltage,40L·h^-1of ventilation rateand1mg·L^-1of MB initial concentration with a mole ratio of activated carbon to Tielement in precursor bing10%, the photoelectrocatalytic degradation efficiency of MBis the highest, the degradation rate of MB could reach99%in150min. Meanwhile, it isalso find that MB molecuars are oxidated by free radicals in the process ofphotoelectrocatalytic degradation and occurred in the C=N bond rupture demethylation,and finally are degraded into H2O, CO2and ions such as SO42, NO3and Cl.The porous Ag-TiO₂film coated foam nickel （PATFN） was successfully preparedon foam nickel substrates by a hard-template method with using activated carbon aspore-forming agent. The modified porous Ag-TiO₂thin films coated foam nickel werecharacterized by the techniques of XRD, SEM, TEM, XPS and TG-DTA. The SEMpatterns indieated that the surface of the porous Ag-TiO₂thin film electrode was unevenand had porous structures; As confirmed by XRD showed that the crystal structure ofTiO₂was still anatase-form, the effects of Ag doping on crystal structure of TiO₂wasnot obvious. The results showed that the PATFN shows the highest photoelectrocatalyticactivity for the degradation of methylene blue when the mole ratio of Ag ion to TiO₂is0.3%In addition, the degradation rate of MB could reach99%in150min when coatingthin film four times and under3V of bias voltage,40L·h^-1of ventilation rate,1mg·L^-1of MB initial concentration and pH=9. Meanwhile, the degradation rate of MB alsocould reach80%after five times recycle of the photoanode.The kinetics of photoelectrocatalytic degradation reaction, photocatalytic degradat-ion reaction and electriccatalytic degradation reaction for MB on porous Ag+-dopedTiO₂thin film photoanode was discussed. Meanwhile, the kinetics of photoelectrocatal-ytic oxidation reaction for different initial concentration of MB was studied. The resultsshowed that the catalytic kinetic equation followed the equation of Langmuir-Hinshelw-ood equation.The catalytic kinetic equation is y=7.07x+23.85, the photoelectrocata-lytic surface reaction rate constant is kc=0.1414mg·L^-1·min^-1, and the adsorptionbalance constant is Kc=0.299L·mg^-1.