低温氨气气氛热处理对介孔纳米TiO_2空心球光催化性能的影响

Effect of Low-Temperature Ammonia Atmosphere Heat Treatment on Photocatalytic Performance of Mesoporous Hollow Spherical TiO_2 Nanoparticles

先采用水热法制备介孔纳米TiO_2空心球,再在低温氨气气氛下对其进行退火处理得到N掺杂和氢化共同作用的N-H-TiO_2。通过XRD、SEM、TEM、XPS、PL、UV-Vis等手段对其结构和形貌进行表征,并评价了其降解气相苯的光催化性能。TEM分析表明,低温氨气气氛热处理可导致介孔纳米TiO_2空心球表面产生无序层,即氢化;XPS分析表明,较低煅烧温度下N原子作为间隙位掺杂。氢化产生的非晶层及N掺杂引入的氧空位使得介孔纳米TiO_2空心球表面的活性位点增加,有利于吸附小分子物质(如O_2、H_2O等),从而在介孔纳米TiO_2空心球表面生成强氧化剂和还原剂,可进行彻底的氧化还原反应,因而表现出优异的光催化性能。

Firstly,mesoporous hollow spherical TiO_2 nanoparticles were prepared by a hydrothermal method.Then,N-H-TiO_2 nanoparticles were prepared by annealing treatment in a low-temperature ammonia atmosphere.The structure and morphology of N-H-TiO_2 nanoparticles were characterized by XRD,SEM,TEM,XPS,PL and UV-Vis.The photocatalytic performance of N-H-TiO_2 nanoparticles was evaluated by photocatalytic decomposition of gaseous benzene.TEM Analysis indicated that heat treatment in the low-temperature ammonia atmosphere could lead to disordered layer on the surface of mesoporous hollow spherical TiO_2 nanoparticles.XPS Analysis indicated that nitrogen atoms were interstitial doped in TiO_2 nanoparticles at a low calcination temperature.The amorphous layer by hydrogenation and oxygen vacancy by nitrogen doping led to increase the number of active sites on the surface of mesoporous hollow spherical TiO_2 nanoparticles and promoted the adsorption of small molecules such as O_2,H_2 O,etc.The superior photocatalytic performance could be attributed to thorough redox reaction by the powerful oxidant and reductant on the surface of mesoporous hollow spherical TiO_2 nanoparticles.