采用固相法制备氮掺杂SrTiO3,并用浸渍氢气还原法制备了不同NiO、CoO负载量的N-SrTiO3异质结复合光催化剂,采用XRD、SEM、荧光光谱(FS)、紫外可见漫反射光谱(UV-Vis DRS)对其进行表征和分析,考察了在模拟太阳光下产氢活性及其变化规律,同时探讨了负载物的不同处理方法对光催化剂产氢活性的影响. 结果表明,氧化物的负载先氢还原后氧化处理较直接氧化处理有更高的光催化活性;所制备的NiO/N-SrTiO3、CoO/N-SrTiO3复合催化剂较单一催化剂有更高的产氢活性,当负载量分别为1.0wt%、0.5wt%时达最佳产氢活性,6h内的产氢量分别是未改性N-SrTiO3样品的4.2、4.9倍. 导致产氢率提高的主要原因是由于负载金属氧化物在两相界面处形成的异质结成为光催化反应中光生电子和空穴的单向转移通道,促使光生电荷有效分离,提高了复合催化剂的光催化活性.
Nitrogen doped SrTiO3 was prepared by solid phase method, and NiO(CoO)/N-SrTiO3 heterojunction complex catalysts with different NiO or CoO loading contents were further obtained via impregnation-hydrogen reduction method. The as-obtained photocatalysts were characterized by XRD, SEM, UV-Vis DRS and Fluorescence spectrum techniques. The photocatalytic hydrogen generation activity and the variation laws under simulated sunlight irradiation were investigated. The effect of different treatment methods of loading NiO on hydrogen generation activity of nitrogen doped SrTiO3 was also studied. The results demonstrate that the photocatalytic activity of the oxides loaded complex catalyst treated by hydrogen reduction firstly and then oxidation is higher than that of the oxides loaded complex catalyst treated by direct oxidation. Comparing with the single catalysts, the asprepared NiO/N-SrTiO3, CoO/N-SrTiO3 complex photocatalysts exhibit higher photocatalytic hydrogen generation activity under simulated sunlight irradiation. The optimal photocatalytic activity of hydrogen production is achieved when the loaded mass percentage is 1.0wt%, 0.5wt% respectively and the amount of hydrogen within 6h is 4.2, 4.9 times more than that of unloaded samples. The reason is that the heterojunction structure formed at the interface of two phases can act as the convenient unilateralism channel for the transfer of photogenerated electrons and holes in the process of photocatalytic reaction after loading the metal oxides, leading to the effective separation of photogenerated carriers, so as to enhance the photocatalytic activity of catalysts.