Gegova-Dzhurkova Radka, Nesheva Diana, Stambolova Irina, Zaharieva Katerina, Dzhurkov Valeri, Miloushev Ilko
G. Nadjakov Institute of Solid State Physics, Bulgarian Academy of Sciences, 1784 Sofia, Bulgaria.
Institute of General and Inorganic Chemistry, Bulgarian Academy of Sciences, 1113 Sofia, Bulgaria.
Molecules. 2024 Aug 24;29(17):4005. doi: 10.3390/molecules29174005.
Semiconductor oxides are frequently used as active photocatalysts for the degradation of organic agents in water polluted by domestic industry. In this study, sol-gel ZnO thin films with a grain size in the range of 7.5-15.7 nm were prepared by applying a novel two-step drying procedure involving hot air treatment at 90-95 °C followed by conventional furnace drying at 140 °C. For comparison, layers were made by standard furnace drying. The effect of hot air treatment on the film surface morphology, transparency, and photocatalytic behavior during the degradation of Malachite Green azo dye in water under ultraviolet or visible light illumination is explored. The films treated with hot air demonstrate significantly better photocatalytic activity under ultraviolet irradiation than the furnace-dried films, which is comparable with the activity of unmodified ZnO nanocrystal powders. The achieved percentage of degradation is 78-82% under ultraviolet illumination and 85-90% under visible light illumination. Multiple usages of the hot air-treated films (up to six photocatalytic cycles) are demonstrated, indicating improved photo-corrosion resistance. The observed high photocatalytic activity and good photo-corrosion stability are related to the hot air treatment, which causes a reduction of oxygen vacancies and other defects and the formation of interstitial oxygen and/or zinc vacancies in the films.
半导体氧化物经常被用作活性光催化剂，用于降解受家庭工业污染的水中的有机物质。在本研究中，通过采用一种新颖的两步干燥程序制备了晶粒尺寸在7.5 - 15.7纳米范围内的溶胶 - 凝胶ZnO薄膜，该程序包括在90 - 95°C下进行热风处理，然后在140°C下进行传统的炉内干燥。为了进行比较，采用标准炉内干燥制备了薄膜层。研究了热风处理对薄膜表面形态、透明度以及在紫外光或可见光照射下水中孔雀石绿偶氮染料降解过程中的光催化行为的影响。经热风处理的薄膜在紫外光照射下表现出比炉内干燥薄膜显著更好的光催化活性，这与未改性的ZnO纳米晶体粉末的活性相当。在紫外光照射下实现的降解百分比为78 - 82%，在可见光照射下为85 - 90%。展示了经热风处理的薄膜的多次使用（多达六个光催化循环），表明其耐光腐蚀性能得到改善。观察到的高光催化活性和良好的光腐蚀稳定性与热风处理有关，热风处理导致薄膜中氧空位和其他缺陷的减少以及间隙氧和/或锌空位的形成。
