The Application Of TiO₂ Composite Nano-array To Photocatalytic Fuel Cell

As the rapid growth of industrialization and urbanization,a large amount of problems have been brought out,especially energy shortage and water contamination.The research of photocatalytic fuel cell?PFC?,which combines the technologies of photocatalysis,photoelectrocatalysis,fuel cells synthetically to achieve multiple and successive conversion of optical energy to chemical energy to electrical energy.PFC can generate electric energy while degrading sewage.The whole process only uses light energy as a driving force and has broad application prospects.Anode materials are the key factors that restrict the performance of PFC,so it is important to synthesize highly active photoanode materials that respond to visible light.In this paper,different morphologies of TiO₂ nanotube arrays were prepared by anodic oxidation in different fluorine-containing electrolysis processes.In the ethylene glycol electrolyte containing ammonium fluoride,a highly ordered titanium dioxide nanotube array with clean top surface was obtained by a two-step anodization approach.The TiO₂ nanotube array has an average diameter of 100 to 120nm and a wall thickness of about 5nm,and a tube density of 1.2×10⁹/cm².It is a good photocatalyst and can be used as an anode material for photocatalytic fuel cells and it will be used as the base material for further research.The TiO₂@MoS₂ and TiO₂@MoO₃ semiconductor composite nano-arrays were synthesized by hydrothermal method,and the crystal structure and chemical bond valence state of the composite nanomaterials were investigated by Scanning Electron Microscope,X-Ray Diffraction and X-ray Photoelectron Spectroscopy.The actual wastewater experiments were carried out on TiO₂@MoS₂ and TiO₂@MoO₃.The results show that the performance of TiO₂@MoS₂ and TiO₂@MoO₃ are improved compared with TiO₂ nanotube array,and the performance of TiO₂@MoS₂ composite is the best.Three kinds of TiO₂-metal composite nano-arrays were prepared by magnetron sputtering technology.The experimental conditions were optimized by controlling the sputtering time and used as anode materials for photocatalytic fuel cells to study their electrical properties.The selected metal targets were copper,nickel and silver,and the sputtering times were controlled at 10 s,30s and 60s,respectively.The experimental results show that the sputtering time affects its morphology.Ni and Cu have the best performance at 30s sputtering time,and Ag can achieve optimal performance when sputtered for 10s.The maximum output voltage of the PFC system composed of Ag/TiO₂ composite nano-array as anode material can reach 400mV under visible light,and the degradation rate of COD in actual wastewater is 94%within 2 hours.In summary,the modified TiO₂ nanotube array by semiconductors and metals can improve the power generation and COD degradation properties of PFC under visible light.Its simple and economical preparation process makes it possible to industrialize and expand PFC.