Enesca Alexandru, Andronic Luminita
Product Design, Mechatronics and Environmental Department, Transilvania University of Brasov, Eroilor 29 Street, 35000 Brasov, Romania.
Nanomaterials (Basel). 2022 Aug 1;12(15):2648. doi: 10.3390/nano12152648.
A three-steps sol-gel method was used to obtain a CuO/SnO/WO heterostructure powder, deposited as film by spray pyrolysis. The porous morphology of the final heterostructure was constructed starting with fiber-like WO acting as substrate for SnO development. The SnO/WO sample provide nucleation and grew sites for CuO formation. Diffraction evaluation indicated that all samples contained crystalline structures with crystallite size varying from 42.4 Å (CuO) to 81.8 Å (WO). Elemental analysis confirmed that the samples were homogeneous in composition and had an oxygen excess due to the annealing treatments. Photocatalytic properties were tested in the presence of three pesticides-pirimicarb, S-metolachlor (S-MCh), and metalaxyl (MET)-chosen based on their resilience and toxicity. The photocatalytic activity of the CuO/SnO/WO heterostructure was compared with WO, SnO, CuO, CuO/SnO, CuO/WO, and SnO/WO samples. The results indicated that the three-component heterostructure had the highest photocatalytic efficiency toward all pesticides. The highest photocatalytic efficiency was obtained toward S-MCh (86%) using a CuO/SnO/WO sample and the lowest correspond to MET (8.2%) removal using a CuO monocomponent sample. TOC analysis indicated that not all the removal efficiency could be attributed to mineralization, and by-product formation is possible. CuO/SnO/WO is able to induce 81.3% mineralization of S-MCh, while CuO exhibited 5.7% mineralization of S-MCh. The three-run cyclic tests showed that CuO/SnO/WO, WO, and SnO/WO exhibited good photocatalytic stability without requiring additional procedures. The photocatalytic mechanism corresponds to a Z-scheme charge transfer based on a three-component structure, where CuO exhibits reduction potential responsible for O production and WO has oxidation potential responsible for HO· generation.
采用三步溶胶-凝胶法制备了CuO/SnO/WO异质结构粉末，并通过喷雾热解法将其沉积成膜。最终异质结构的多孔形态是从纤维状WO开始构建的，WO作为SnO生长的基底。SnO/WO样品为CuO的形成提供了成核和生长位点。衍射评估表明，所有样品均含有晶体结构，微晶尺寸从42.4 Å（CuO）到81.8 Å（WO）不等。元素分析证实，样品在成分上是均匀的，并且由于退火处理而存在氧过量。在基于三种农药抗逆性和毒性选择的抗蚜威、S-异丙甲草胺（S-MCh）和甲霜灵（MET）存在下测试了光催化性能。将CuO/SnO/WO异质结构的光催化活性与WO、SnO、CuO、CuO/SnO、CuO/WO和SnO/WO样品进行了比较。结果表明，三元异质结构对所有农药具有最高的光催化效率。使用CuO/SnO/WO样品对S-MCh的光催化效率最高（86%），而使用CuO单组分样品对MET的光催化效率最低（8.2%）。总有机碳分析表明，并非所有的去除效率都可归因于矿化，可能会形成副产物。CuO/SnO/WO能够使S-MCh矿化81.3%，而CuO对S-MCh的矿化率为5.7%。三轮循环测试表明，CuO/SnO/WO、WO和SnO/WO表现出良好的光催化稳定性，无需额外的处理。光催化机理对应于基于三元结构的Z型电荷转移，其中CuO表现出负责O生成的还原电位，WO具有负责HO·生成的氧化电位。
