Assaouka Hippolyte Todou, Daawe Daniel Manhouli, Fomekong Roussin Lontio, Nsangou Issah Njiawouo, Kouotou Patrick Mountapmbeme
Department of Chemistry, Faculty of Sciences, University of Maroua, P.O. Box.: 55, Maroua, Cameroon.
National Advanced School of Engineering, University of Maroua, P.O. Box. 46, Maroua, Cameroon.
Heliyon. 2022 Sep 19;8(9):e10689. doi: 10.1016/j.heliyon.2022.e10689. eCollection 2022 Sep.
Herein CuO nanoparticles (NPs) with nanostructures were prepared by precipitation method using hydrate copper sulfate (CuSO.5HO) and sodium hydroxide followed by heat treatment at 400 °C. The as-prepared CuO NPs with nanostructures were investigated using X-ray diffraction (XRD), Fourier Transformed Infra-red spectroscopy (FTIR), Raman spectroscopy, Scanning electron microscopy (SEM), X-ray photochemical spectroscopy (XPS), Energy dispersive spectroscopy (EDS), and Ultra-violet-visible (UV-vis) spectroscopy. In order to evaluate the reducibility, temperature programmed reduction (H-TPR) was applied. More importantly, CuO NPs was successfully tested as catalyst towards the total conversion of carbon monoxide (CO) and toluene (CH). Both XRD and Raman analysis as well as FTIR show that the sample exhibited a monoclinic spinel structure. SEM images indicate that CuO NPs are well-covered by grains size exhibiting homogeneous morphology composed of very fine interconnected particles with an apparent porosity. The sample was made up of Cu and O, according to the XPS and EDS measurements. The band gap energy obtained from optical property analysis is ∼2.65 eV. The catalytic performances of CuO NPs can be assigned to the combined effects of crystal structure, morphology, surface oxygen mobility, redox property and the higher specific surface area (∼87 m/g). More precisely XPS and H-TPR data suggests that, the conversion of CO and CH over CuO NPs follows a Mars-van Krevelen type mechanism. More importantly CuO NPs catalysts is reusable and exhibited good stability in the prolonged isothermal test. Thus, CuO NPs is confirmed as an efficient and inexpensive catalysts for CO and CH conversion at low temperatures.
本文采用水合硫酸铜（CuSO₄·5H₂O）和氢氧化钠通过沉淀法制备了具有纳米结构的氧化铜纳米颗粒（NPs），随后在400℃下进行热处理。使用X射线衍射（XRD）、傅里叶变换红外光谱（FTIR）、拉曼光谱、扫描电子显微镜（SEM）、X射线光化学光谱（XPS）、能量色散光谱（EDS）和紫外可见（UV-vis）光谱对所制备的具有纳米结构的氧化铜纳米颗粒进行了研究。为了评估其还原性能，采用了程序升温还原（H₂-TPR）。更重要的是，氧化铜纳米颗粒作为一氧化碳（CO）和甲苯（C₆H₅CH₃）完全转化的催化剂进行了成功测试。XRD和拉曼分析以及FTIR均表明该样品呈现单斜尖晶石结构。SEM图像表明氧化铜纳米颗粒被晶粒尺寸良好覆盖，呈现出由非常细小的相互连接颗粒组成的均匀形态，具有明显的孔隙率。根据XPS和EDS测量，该样品由铜和氧组成。通过光学性质分析获得的带隙能量约为2.65 eV。氧化铜纳米颗粒的催化性能可归因于晶体结构、形态、表面氧迁移率、氧化还原性质和较高的比表面积（约87 m²/g）的综合作用。更确切地说，XPS和H₂-TPR数据表明，一氧化碳和甲苯在氧化铜纳米颗粒上的转化遵循Mars-van Krevelen型机理。更重要的是，氧化铜纳米颗粒催化剂可重复使用，并且在长时间等温测试中表现出良好的稳定性。因此，氧化铜纳米颗粒被确认为低温下一氧化碳和甲苯转化的高效且廉价的催化剂。
