Gold catalysts supported on cerium-modified mesoporous zirconia for total toluene oxidation. Effect of Ce/Zr molar ratio
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Gold catalysts supported on cerium‑modified mesoporous zirconia for total toluene oxidation. Effect of Ce/Zr molar ratio H. Azzi1,2 · L. Chérif1 · S. Siffert3 Received: 28 July 2020 / Accepted: 23 October 2020 © Springer Nature B.V. 2020
Abstract Our study focused on the synthesis of gold catalysts supported on mixed Ce–ZrO2 (Ce/Zr = 0, 0.1, 0.4 and 0.9) mesoporous, which are mainly potential in the total oxidation of toluene and other volatile organic compounds. The mesoporous Ce–ZrO2 oxides (Ce/Zr = 0, 0.1, 0.4 and 0.9) were prepared via soft template strategy, using a triblock copolymer as a template. 1% of Au was loaded on mixed oxide mesoporous by deposition precipitation method. Ce–ZrO2 and Au/Ce–ZrO2 (Ce/Zr = 0, 0.1, 0.4 and 0.9) samples were characterized by XRD, N 2 adsorption–desorption, H 2-TPR and MET. The results showed that the dispersion of the gold particles on Ce–ZrO2 depends on the Ce/Zr ratio. These catalysts were then tested in the deep oxidation of toluene oxidation where they exhibited an excellent catalytic activity by complete decomposition of toluene at the reaction temperature equal to 576 K. This activity is correlated with the dispersion of the gold particles; itself is correlated with the Ce/ Zr ratio. Keywords Mesoporous · Ce–ZrO2 · Gold supported · Toluene oxidation
Introduction Volatile organic compounds (VOCs) released in the air during industrial processes are well known as main contributors to atmospheric pollution and are harmful to the quality of human life [1–3]. Catalytic oxidation is one of the most important * H. Azzi hajer.azzi@cuniv‑aintemouchent.dz 1
Laboratoire de Catalyse et Synthèse en Chimie Organique, Université de Tlemcen, BP 119, Tlemcen, Algeria
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Centre Universitaire Ain Témouchent, Institut des Sciences et de la Technologie, BP 284, 46000 Ain Témouchent, Algeria
3
ULCO, UCEIV, 59140 Dunkerque, France
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processes for VOCs elimination since VOCs oxidation takes place over a catalyst at significantly lower temperatures than those required for thermal destruction [4]. Catalytic oxidation of VOCs has been carried through noble metal catalysts or nonnoble metal catalysts, where the noble metal catalysts mostly showed a better catalytic performance [5, 6]. Gold has been considered as proven powerful material when it is highly dispersed on suitable support for various industrial and environmental applications [7]. The state and structure of the support strongly impact the catalytic activity and selectivity of the gold-based catalysts [7]. The choice of efficient support is thus a determining factor to ensure efficient contact between gold and support for high catalytic performance [7]. The Ce–ZrO2 mixed oxides with different Ce/Zr molar ratios have combined properties between C eO2 and ZrO2. They present an important thermal stability, oxygen storage, fluidity and mobility in a modified lattice [8, 9]. In this paper, we have synthesized several mesoporous Ce–ZrO2 supports by a templating sol–gel method with th
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