一步法制备纳米SnO-SnO2复合材料及其光催化性能增强机制的光生载流子动力学

半导体复合材料中的光生载流子动力学过程是影响其光催化性能的重要因素之一。该工作以二水合氯化亚锡（SnCl₂·2H₂O）为原料，NaOH为沉淀剂，采用一步溶剂热法制备了Sn的氧化物纳米SnO-SnO₂复合材料，并利用SEM、XRD、TEM和Uv-Vis光谱等对产物进行了表征。结果表明，通过控制反应条件可以获得粒径约为10~20 nm的SnO-SnO₂复合材料和粒径约为10 nm的四方相SnO₂颗粒，分散性较好。光催化性能研究表明，纳米SnO-SnO₂复合材料完全催化降解罗丹明B（RhB）的时间比纳米SnO₂颗粒减少50%。针对这一结果，利用瞬态表面光电压（TSPV）技术分别对上述纳米材料的光生载流子动力学过程进行了讨论。结果表明，纳米SnO-SnO₂复合结构的构建可以有效地促进光生载流子的分离，抑制SnO₂表面光生载流子的复合及提高材料表面的光生载流子的寿命，进而显著增强其光催化性能。

One step synthesis of nano SnO-SnO2 composites and the photoinduced charge carrier dynamics for the enhanced photocatalytic performance

The photoinduced charge carrier dynamics is one of the important factors that affect the photocatalytic performace of semiconductor composites. In this work, tin oxides nano-particles were successfully fabricated by one-step solvent thermal method using SnCl₂·2H₂O as raw material and NaOH as precipitant. The fabricated samples were characterized by SEM, XRD, TEM and Uv-Vis spectra. The results show that about 10-20 nm particles size SnO-SnO₂ composites and about 10 nm tetragonal SnO₂ particles can be obtained by adjusting the reaction condition. Photocatalytic degradation performance of the above two nano-materials has been evaluated by using Rhodamine (RhB) as the degradation agent. The degradation time of RhB can be reduced by 50% by using nano SnO-SnO₂ composites as photocatalyst compared with pure nano SnO₂ particles. For further studying the mechanism for this result, transient surface photovoltage (TSPV) technique has been carried out to understand the photoinduced charge carrier dynamics of the resulting materials. The corresponding results show that the photoinduced charge carrier separation has been enhanced, the surface recombination of photoinduced charge carrier has been reduced, and the lifetime of photoinduced charge carrier on the material surface is prolonged by building the nano SnO-SnO₂ composites. Finally, the consequent photocatalystic performance is enhanced.