This work described the acquisition of immobilized ZnO semiconductors using the slip casting technique, for application as reusable photocatalysts in the degradation of Rhodamine B. The influence of the heat treatment temperature (800°C, 900°C, and 1000°C) on the physical, thermal, microstructural, and photocatalytic properties was investigated. All samples presented the wurtzite crystal structure, and the surface was completely absent of organic matter residues. The samples presented band gap values around 3.2 eV. The ones heat treated at 800°C showed lower density (3.40 g/cm³, corresponding to 60% of the ZnO theoretical density), smaller average grain size, in addition to higher apparent porosity (around 40%). These characteristics provide better photocatalytic activity to the sample heat treated at 800°C, since it promoted 92.2% dye degradation, while samples heat treated at 900°C and 1000°C promoted 81.8% and 54.2% dye degradation, respectively. The integrity of all samples was maintained after the photocatalytic tests. Thus, the reuse capability of the sample with the best photocatalytic performance, that is, the sample heat treated at 800°C, was evaluated in six cycles of photocatalysis. The sample proved to be reusable, promoting degradation of practically 100% of the dye after the third cycle of reuse.

中文翻译：

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通过滑模铸造获得的ZnO半导体：在光催化中的应用和重复使用

这项工作描述了使用滑模铸造技术获得固定化ZnO半导体的方法，该技术可作为可重复使用的光催化剂用于罗丹明B的降解中。热处理温度（800°C，900°C和1000°C）对热定型工艺的影响。研究了物理，热，微结构和光催化性能。所有样品均显示纤锌矿晶体结构，并且表面完全没有有机物残留。样品的带隙值约为3.2 eV。在800°C热处理的合金的密度较低（3.40 g / cm ³，相当于ZnO理论密度的60％），较小的平均晶粒尺寸以及较高的表观孔隙率（约40％）。这些特性为在800°C热处理的样品提供了更好的光催化活性，因为它促进了92.2％的染料降解，而在900°C和1000°C热处理的样品分别促进了81.8％和54.2％的染料降解。在光催化测试后，所有样品的完整性得以保持。因此，在六个光催化循环中评价了具有最佳光催化性能的样品的再利用能力，即在800℃下热处理的样品。样品被证明是可重复使用的，在第三次重复使用之后，实际上促进了100％的染料降解。