Research On The Effect Of Al Surface Plasmon Resonance On The Photocatalytic Performance Of TiO₂

The pollution of rivers by organic matter will cause serious damage to the ecosystem and life safety,so it is necessary to take relevant measures to remove organic matter from wastewater.In organic wastewater treatment,TiO₂photocatalytic method has the advantages of simple operation,fast degradation rate and no secondary pollution,but it is also limited by the low solar energy utilization and low quantum efficiency.Among the many methods to enhance the photocatalytic performance of TiO₂,metal surface plasmon resonance shows excellent results.The noble metals Au and Ag are widely studied,but their costs are high and surface plasmon resonance cannot realize the enhancement in the UV region.Non-noble metal Al can undergo strong surface plasmon resonance in the UV region to enhance TiO₂photocatalytic performance,but the current studies on Al surface plasmon resonance are focused on depositing Al nanoparticles on the substrate,which requires large-scale lithography equipment during the experimental process and the ratio of Al nanoparticles to TiO₂is difficult to control.Therefore,this paper proposes the use of monodisperse Al nanoparticles composited with TiO₂and their ratios are regulated to prepare Al-NPs/TiO₂nanocomposites with high photocatalytic activity.The main contents of the study are as follows:（1）Al nanoparticles are prepared by electro-explosion method and monodispersed using PS-COOH solution,followed by the simulation of optical properties of Al nanoparticles by Finite Difference Time Domain method as a way to understand the factors affecting the wavelength range of the surface plasmon resonance of Al nanoparticles.（2）Monodisperse Al nanoparticles are composited with TiO₂nanoparticles by regulating three factors:ligand type,particle size and mass of Al nanoparticles to make the Al nanoparticles at a particle size of 200 nm and a mass of 13.5 mg,the Al-NPs/TiO₂nanocomposites formed when glutathione was selected as the ligand showed the best photocatalytic degradation of methylene blue solution with an efficiency of 98.99%at 50min of light exposure.（3）The photocatalytic mechanism of Al nanoparticles enhanced TiO₂is investigated by theoretical combined with experimental methods.It is proposed that one reason for the enhancement of photocatalytic efficiency of semiconductor TiO₂by Al nanoparticles is that Al nanoparticles compound with TiO₂to form a Schottky junction,which reduces the possibility of photogenerated electron and hole recombining,thus improving the efficiency of photocatalytic reaction.The other is that the near-field enhancement of surface plasmon resonance effect of Al nanoparticles increase the light absorption of TiO₂,which makes it produce more electrons and holes under light,thus improving the photocatalytic performance of TiO₂.