Sn-Doped α-Fe2O3 Photocatalyst containing Oxygen Vacancy for Water-splitting
- 2017年第23卷 
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-Fe2O3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SnCl4制备α-Fe2O3的方法研究了Sn掺杂对氧空位型α-Fe2O3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α-Fe2O3在1.23V vs. RHE时的电流密度分别是氮气氛围中退火未掺杂α-Fe2O3的35倍和空气氛围中退火Sn掺杂α-Fe2O3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 550 °C and 1.23 V (vs. RHE) was 35 times greater than that of pristine α-Fe2O3 annealed in N2 at 550 °C and 15 times greater than that of Sn-doping α-Fe2O3 annealed in air at 550 °C, 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 of α-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.