Konsolakis M, Carabineiro S A C, Marnellos G E, Asad M F, Soares O S G P, Pereira M F R, Órfão J J M, Figueiredo J L
School of Production Engineering and Management, Technical University of Crete, 73100 Chania, Greece.
Laboratório de Catálise e Materiais (LCM), Laboratório Associado LSRE-LCM, Faculdade de Engenharia, Universidade do Porto, 4200-465 Porto, Portugal.
J Colloid Interface Sci. 2017 Jun 15;496:141-149. doi: 10.1016/j.jcis.2017.02.014. Epub 2017 Feb 10.
Cobalt-cerium mixed oxides were prepared by the wet impregnation method and evaluated for volatile organic compounds (VOCs) abatement, using ethyl acetate (EtAc) as model molecule. The impact of Co content on the physicochemical characteristics of catalysts and EtAc conversion was investigated. The materials were characterized by various techniques, including N adsorption at -196°C, scanning electron microscopy (SEM), X-ray diffraction (XRD), H-temperature programmed reduction (H-TPR) and X-ray photoelectron spectroscopy (XPS) to reveal the structure-activity relationship. The obtained results showed the superiority of mixed oxides compared to bare CeO and CoO, demonstrating a synergistic effect. The optimum oxidation performance was achieved with the sample containing 20wt.% Co (Co/Ce atomic ratio of ca. 0.75), in which complete conversion of EtAc was attained at 260°C. In contrast, temperatures above 300°C were required to achieve 100% conversion over the single oxides. Notably, a strong relationship between both the: (i) relative population, and (ii) facile reduction of lattice oxygen with the ethyl acetate oxidation activity was found, highlighting the key role of loosely bound oxygen species on VOCs oxidation. A synergistic Co-Ce interaction can be accounted for the enhanced reducibility of mixed oxides, linked with the increased mobility of lattice oxygen.
采用湿浸渍法制备了钴铈混合氧化物，并以乙酸乙酯（EtAc）为模型分子，对其挥发性有机化合物（VOCs）的去除性能进行了评估。研究了钴含量对催化剂物理化学特性及乙酸乙酯转化率的影响。通过多种技术对材料进行了表征，包括在-196°C下的N吸附、扫描电子显微镜（SEM）、X射线衍射（XRD）、H程序升温还原（H-TPR）和X射线光电子能谱（XPS），以揭示结构-活性关系。所得结果表明，混合氧化物相对于纯CeO和CoO具有优越性，显示出协同效应。含20wt.% Co（Co/Ce原子比约为0.75）的样品实现了最佳氧化性能，在260°C时乙酸乙酯完全转化。相比之下，单一氧化物需要300°C以上的温度才能实现100%转化。值得注意的是，发现（i）相对含量和（ii）晶格氧的易还原程度与乙酸乙酯氧化活性之间存在密切关系，突出了松散结合的氧物种在VOCs氧化中的关键作用。协同的Co-Ce相互作用可解释混合氧化物还原能力的增强，这与晶格氧迁移率的增加有关。
