Photoelectronic Catalytic Properties Of ZnFe₂O₄/TiO₂/Flake Graphite Electrode Particles

TiO2has become the most promising photocatalyst because of its high catalytic activity, high chemical stability, security, non-toxicity, low price and easy preparation, etc. However, it’s difficult for TiO2to act as a photocatalyst because of its two fatal problems:(1) photocatalytic efficiency is not high;(2) there’s a contradiction between TiO2photocatalyst fixed and its photocatalytic efficiency. The experiment innova-tive ly loaded the photocatalyst on particle electrodes and cleverly combined the pho-tocatalytic with electrochemical reaction technology to constitute a photoelectroca-talysis system of three-dimensional electrode, where the photocatalyst was fixed and photocatalytic efficiency was improved, in order to achieve synergistic effects of cat-alytic degradation of organic matter.A three-phase three-dimensional photoelectrocatalysis system was constituted, using the supported ZnFe2O4/TiO2/flake graphite prepared by sol-gel method as par-ticle electrode, the same area titanium flake as central electrode of photoelectroca-talysis system, the xenon lamp as light source, the air compressor to provide oxygen source, sodium solution as electrolyte and Rhodamine B(RhB) solution as target degradants. The experiment of RhB degradation was carried out on the self-assembly three-dimensional electrode photoelectric catalytic reactor.The specific surface area of loaded flake graphite was2.7479m2/g, while the specific surface area of naked flake graphite was1.7605m2/g. SEM graph showed there was a layer of porous nanoparticles on the loaded flake graphite surface. XRD graph showed that the flake graphite had been loaded anatase TiO2successfully. Chemical analysis from XPS showed that the loaded flake graphite contains anatase TiO2and small amount of ZnFe2O4.The experiment prepared photoelectrocatalysis particle electrodes of different carrier particles, different ZnFe2O4content and different loading times, and studied its performance of photoelectrocatalytic. The results showed that, when the photoelec-trocatalysis system used flake graphite as the carrier and flake graphite was loaded ZnFe2O4for2times with content of3%, it worked best. In this study, the joint system reached a synergistic effect. The laboratory prepared particle electrode also showed good photoelectrochemical stability.Experiments investigated the effects of electrolyte concentration, applied voltage, the dosage of particle electrode, initial pH of solution and the initial concentration of RhB on the photoelectrocatalytic degradation of RhB. The experiment showed that under the best conditions of electrolyte concentration for0.01mol/L, applied voltage for15V, aeration rate for20mL/min, particle electrode dosage for10g/L and initial pH=2, the removal ratios of RhB came to99%in30minutes.