Study On The Preparation And Electrocatalytic Properties Of Titanium-based Metal Oxide Electrodes

The anode materials are one of the key factors affecting the application of electrocatalytic oxidation technology in water treatment.In this paper,titanium-based TiO₂ nanotube array?Ti/TNTs?were developed as the substrate material of anode,and the anodes were investigated by the methods of doping and modificating.The concrete results are as follows:Titanium dioxide nanotubes array?Ti/TNTs?were prepared using anodic oxidation method,and the effects of several factors such as pH,oxidation voltage and temperature on the morphology of TiO₂ nanotubes?TNTs?were investigated.Several parameters affecting TNTs formation were optimized by means of uniform experiment.The results showed that the TNTs was long,uniform and orderly arrayed under the experimental conditions of the oxidation voltage 35V,the oxidation time 2.5h,the electrolyte composition of 0.85wt%NH₄F+3vol%H₂O,and the initial pH=9,This Ti/TNTs also exhibited the best electrocatalytic oxidation capacity.At the current density of 10mA/cm²,the removal rate of methylene blue?MB?was 64.1%within 180min.The graphene-hydrogel modified Ti/TNTs-Sb-SnO₂-rGO electrode was prepared using layer by layer coating of"SbCl₃-SnCl₄"mixture gel solution and graphene precursor solution on the obtained Ti/TNTs as anode substrates.The graphene-hydrogel bone structure was constructed by graphene precursor solution fast evaporating of solvent at high temperature.The effect of graphene?rGO?on electrode performance and morphology was studied in detail.Compared with the Ti/TNTs-Sb-SnO₂ electrode,the conductivity of Ti/TNTs-Sb-SnO₂-rGO was significantly increased because of the presence of graphene.Graphene can effectively reduce the aggregation of metal and metal oxide particles,which were small and distributed like cluster on the electrode surface.Ti/TNTs-Sb-SnO₂-rGO electrode was shown the excellent performance of catalytic and stability.For example,the oxygen evolution potential was improved to 2.1V,acceleration life was 9.0h.Methylene blue was used as a model molecular to evaluate the efficiency of Ti/TNTs-Sb-SnO₂-rGO electrode.Methylene blue was effectively degraded by this electrode within 60 min,and the removal rate reached 97%.The current efficiency was 31%.Ti/TNTs-La_xSb_1-x-SnO₂-rGOelectrodewaspreparedbyco-dopeding Ti/TNTs-Sb-SnO₂-rGO with rare earth elements La.The influence of doping amount of La was studied for the performance of the electrode.It was shown that Ti/TNTs-La_xSb_1-x-SnO₂-rGO electrode had the best synergistic effect of La and Sb when the electrode was prepared at the mole percentage of La₂₀Sb₈₀.The electrode displayed high oxygen evolution potential?2.5V?,outstanding catalytic activity and excellent stability.The influences of the initial concentration of methylene blue,initial pH value of solution,temperature and current density were systematically studied to optimize the catalytic performance of Ti/TNTs-La_xSb_1-x-SnO₂-rGO electrode.It was indicated that the best efficiency of degradation of methylene blue was achieved when the initial concentration of 10mg/L,pH=9,the reaction temperature of 20?,the current density of5mA/cm²,and the removal rate of methylene blue reached 100%within 60min.