Preparation Of Modified TiO₂ Nanotube Array Light Anode And Photoelectrochemical Performance Research

In recent years,as an important photochemical material,titanium dioxide has been widely used in the catalytic treatment of environmental problems,solar cell and photolysis of water,due to its excellent photochemical properties,fast electronic transmission rate,low price,simple preparation and low toxicity.In this paper,highly ordered titanium dioxide nanotube arrays were prepared by two times anodic oxidation method.Ga₂O₃,MgO and MgTiO₃ were deposited on TiO₂ by pulse electrodeposition method,thus the composite semiconductor modification was realized.The photochemical properties and cathodic protection of photoelectrochemical?PEC?were also studied.The main contents are as follows:?1?TiO₂ nanotube arrays were prepared by conventional primary anodization method.The prepared arrays were removed by ultrasonic in a certain concentration of hydrochloric acid solution,and a uniform pit Ti substrate was obtained.On the basis of the second anodization,the TiO₂ nanotube array is highly ordered,the tube wall is thin,and the tube mouth is large.The photo-chemical property of the TiO₂ nanotube array is increased by 0.5 times as compared with the one-time anode oxidation TiO₂ nanotube array,and better template substrate is provided for the subsequent oxide deposition.?2?In order to further enhance the photoelectrochemical performance of TiO₂,the Ga₂O₃/TiO₂ nanotube array was prepared by pulsed electrodeposition.With the deposition times and annealing temperature changing,the photochemical properties show a certain regularity.The carrier density of the Ga₂O₃/TiO₂ nanotube arrays prepared by the optimal deposition times and annealing temperature is greatly increased without destroying the highly ordered array structure.The photo current density is 1.5times of that of the double-anode oxidation pure TiO₂ nanotube array,and the photoelectrochemical performance is effectively improved.?3?In order to further improve the photocathodic protection of TiO₂ NTs,TiO₂nanotube arrays were modified by mg oxides.It is found that annealing temperature has a great influence on the morphology of the composites,and the coexistence of MgO,rutile TiO₂ and anatase TiO₂ appears at 600?.Photocathodic protection tests show that under simulated solar light exposure of 100mWU AM 1.5G),the transient current density is 0.25 mA/cm² by MgO/TiO₂ NTs coupled with 304 stainless steel optoelectronic pole.After stabilization,it still reached 0.07 Ma/cm²,more than seven times that of TiO₂ nanotube array.The negative shift of OCP=-420 mV for photocathodic protection is twice as high as that of pure TiO₂ nanotube arrays.?4?The MgTiO₃/TiO₂ NTs core-shell heterojunction nanotube arrays were fabricated by further increasing the annealing temperature to 700?.Under the simulated solar irradiation?100 m WU AM 1.5G?and the bias voltage of 0 V,the photoinduced current density of MgTiO₃/TiO₂ NTs coupled with 304 stainless steel is more than 8times that of the second anodized TiO₂ nanotube array.The OCP of photocathodic protection shifted to-470 mV,three times as much as that of TiO₂ nanotube array.The experimental results show that it is feasible to deposit metal oxides on TiO₂nanotube arrays by pulse deposition.By adjusting the deposition times and annealing temperature,the photochemical properties and photocathodic protection properties of semiconductor materials can be improved,and the modification mechanism of different oxides is also further explored.