Study On Fabrication And Photocatalytic Performance Of Nanoporous Single-Crystalline SrTiO₃ And Its Au-coupled Plasmonic Photocatalyst

As an effective pollution control technique,photocatalysis has attracted extensive attention because of environmental-friendly and complete degradation advantages.The common photocatalyst SrTiO3 suffers from several defects,such as high energy consumption in the synthesis,low surface area and few active sites of samples synthesized by traditional method,and narrow optical absorption,which limit its practical application.Porous materials can enhance the reactant adsorption and offer more active sites due to its large surface area and high pore volume.Single-crystalline nature enables material to promote the separation of the photogenerated carriers and to enhance their transfer to surface.The localized surface plasmon resonance(LSPR)effect of Au nanoparticles can extend the visible-light absorption.Additionally,composite material could enhance the separation of photogenerated carriers.In this dissertation,two programs have been carried out as following.(1)Sol-gel alkali-dissolution-exothermal reaction to prepare nanoporous single-crystalline SrTiO3(NP-SC-STO).The lowest crystallized temperature of single-phase SrTiO3 was 53 ? without ethylene glycol(EG)addition.Change the amounts of EG and NaOH in synthesis could adjust the crystallization and surface area of SrTiO3.The sample obtained using 5 ml EG and 5 M NaOH were sphere-like particle with diameter of around 300 nm and specific surface area of 143 m2/g.During the photocatalytic degradation of gaseous isopropanol under UV light irradiation,the acetone and CO2 yields were 315 mmol/h and 31 mmol/h,respectively,which were over twice of that on commercial SrTiO3.(2)Au loaded nanoporous single-crystalline SrTiO3.The visible-light-responsive photocatalyst,Au@nanoporous single-crystalline SrTiO3(Au@NP-SC-STO),was successfully fabricated by photo depositing Au nanoparticles on NP-SC-STO which was prepared from the above-mentioned sol-gel alkali-dissolution-exothermal method.Compared with the commercial SrTiO3 without porous structure,NP-SC-STO exhibits a space confinement effect.The average sizes of Au particles mainly distributed from 5-8 nm and were not enlarged as Au loading amount increasing.The Au@NP-SC-STO showed excellent photocatalytic performance;in particularly,utilized photon number of 5wt%Au@NP-SC-STO(sample loaded with 5wt% of Au)was 466 mmol/h,which was more than 8-folds of that of the most efficient Au loaded commercial Sr TiO3.