Sn掺杂对氧空位型α-Fe_2O_3纳米颗粒光解水性能的影响

Sn-Doped α-Fe_2O_3 Photocatalyst Containing Oxygen Vacancy for Water-Splitting

在退火前未抽真空条件下,采用滴涂法在常压氮气氛围中退火制备了含氧空位的α-Fe_2O_3纳米颗粒.通过在空气和氮气氛围中退火和向前驱体溶液直接加入SnCl_4制备的α-Fe_2O_3的方法研究了Sn掺杂对氧空位型的α-Fe_2O_3纳米颗粒光催化性能的影响.结果表明,氮气氛围中退火Sn掺杂得到的的α-Fe_2O_3在1.23V vs.RHE时的电流密度分别是氮气氛围中退火未掺杂的α-Fe_2O_3的35倍和空气氛围中退火Sn掺杂的α-Fe_2O_3的15倍,氮气氛围中退火和掺杂被证明是获得高催化性能必不可少的条件.Mott-Schottky曲线和交流阻抗谱表明,掺杂和氧空位能增大催化剂的载流子浓度的电导率.在牺牲剂溶液中测试发现,Sn掺杂导致材料的表面反应速率提高是催化剂活性的重要影响因素.

The α-Fe2O3 nanoparticles containing oxygen vacancies were synthesized in atmospheric N2 by dip-dropping method without a high vacuum employed before annealing.The influences of annealing atmosphere and Sn-doping on the photocatalytic performance of α-Fe2O3 nanoparticles were studied by annealing the photocatalyst in N2 or air and adding SnCl4 to the precursor directly.The results showed that the current density of Sn-doping α-Fe2O3 annealed in N2 at 550oC and 1.23 V（vs.RHE） was 35 times greater than that of pristine α-Fe2O3 annealed in N2 at 550 ℃ and 15 times greater than that of Sn-doping α-Fe2O3 annealed in air at 550 oC,which indicated that both Sn-doping and annealing in N2 were indispensible to obtain a good performance for α-Fe2O3 nanoparticles.Mott-Schottky curves and electrochemical impedance spectroscopic data proved that both Sn-doping and oxygen vacancy could lead to the increase of the donors concentration and conductivity,which resulted in the enhanced performance ofα-Fe2O3 nanoparticles.The photocatalytic performance tested in the electrolyte containing sacrifice solvent confirmed that the Sn-doping could facilitate the surface reaction,which was another key factor contributed to the enhanced performance of α-Fe2O3 nanoparticles.