The Synthesis Of TiO₂ Nanotube Arrays Applied In Photoreduction Of CO₂ And The Study Of Concentrated Reaction

Photocatalytic technology can convert CO₂ into hydrocarbons,which puts forward an effective way to solve the increasingly prominent energy shortage and environmental pollution problems.Energy and material are two important factors in the photocatalytic reaction and have caused great concern among researchers in recent years.Based on the anodic oxidation method,TiO₂ nanotube array films were prepared and modified with metal,which were applied on the photocatalytic reduction of CO₂.The concentrated solar reactor system was established to investigate the photoreduction of CO₂ performance on TiO₂ and Pt/TiO₂ catalysts,and ZnO or other semiconductor photocatalysts.Some conclusions are as follows:?1?The TiO₂ nanotube arrays prepared by anodic oxidation method have a high degree of ordered structure and exist anatase phase after calcining at 400?.The XRD and TEM results show that the metal particles are successfully loaded onto the surface of TiO₂ nanotubes without damage of the nanotube structure.?2?The metal-loaded TiO₂ nanotubes can improve the performance of photocatalytic reduction of CO₂,mainly in accelerating the reaction rate or prolonging the equilibrium of the reaction.Among single-metal-loaded TiO₂ nanotubes,Pt/TNTAs have good performance;and double-metal-loaded TiO₂ nanotubes of Pt-Cu/TNTAs,Pt-Ag/TNTAs,Pt-Pd/TNTAs,the yield of CH₄ are 8.7,10.7 and 13.6times higher than that of TiO₂ alone.?3?Concentration can improve the efficiency of photocatalytic conversion of CO₂.The quantum efficiencies?%?of CH₄ on TiO₂ and Pt/TiO₂ are 2.21 and 3.16respectively under non-concentrated condition,and the quantum efficiencies?%?are8.85 and 10.03 respectively under the best concentrated condition.?4?TiO₂,?-Fe₂O₃,WO₃,ZnO and SnO₂ have the highest yield of CH₄ at the concentrating ratio of 12.9,and are 13,18.5,13.8,13.4 and 15 times respectively under the non-concentrated condition.With the increase of light intensity,the activity increased first and then decreased,not best at the focal position of the lens.The reason may be that the catalyst absorbs the incident light to saturation at a certain position.