掺杂稀土元素La对TiO2纳米粉末光催化制氢性能的影响

Influence of Rare Earth La Doping on the Photocatalytic Hydrogen Production Performance for TiO2 Nanoparticles

为了改善TiO2体系的光催化制氢性能,以La元素为掺杂剂,采用溶胶-凝胶法制备了掺杂La的TiO2纳米粉末,并研究了掺杂La对光催化制氢性能的影响。结果表明:La离子的掺入导致TiO2体系吸收边红移,禁带宽度减小;随着La离子的掺入,样品的制氢性能呈现先增大后减小的趋势。当La离子掺杂的摩尔分数为3%时,体系具有最优光催化制氢性能,光催化3h的制氢量达到577.5μmol/g,比未掺杂的TiO2纳米粉末性能增强了4.1倍,且经5次循环利用后仍表现出良好的光催化稳定性。研究同时发现,La离子具有调节TiO2体系表面氧空位浓度的作用。氧空位有利于光生电子的俘获,实现光生载流子分离,从而有利于增强TiO2体系的光催化制氢性能。

To improve the photocatalytic hydrogen production performance of TiO2,rare earth La was chosen as a dopant and La doped TiO2 nanoparticles were prepared by sol-gel method,and then the influence of La doping on the photocatalytic hydrogen production performance for TiO2 was investigated.The results indicated that with the increase of La doping content,the absorption edge exhibited red shift and the band gap of the samples was gradually narrowed.Moreover,the photocatalytic hydrogen production performance gradually increased initially up to 3% of La addition and then decreased with the further increase of La doping content.The hydrogen production rate was enhanced to 577.5 μmol/g at the La content of 3%,which was 4.1 times higher than that of pure TiO2 sample,and the sample exhibited good recyclability.The results also revealed that the surface oxygen vacancy concentration can be modulated by La doping.Surface oxygen vacancy was favorable in capturing the photoinduced electrons during the process of photocatalytic reactions,which was benefit to the separation of photoinduced electrons,and the recombination of photoinduced electrons can be effectively refrained,thus the hydrogen production rate was enhanced.