Starch bio-template synthesis of W-doped CeO 2 catalyst for selective catalytic reduction of NO x with NH 3 : influence
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RESEARCH ARTICLE
Starch bio-template synthesis of W-doped CeO2 catalyst for selective catalytic reduction of NOx with NH3: influence of ignition temperature Zhi-Bo Xiong 1,2
&
Zhen-Zhuang Li 1 & Yan-Ping Du 3 & Cheng-Xu Li 1 & Wei Lu 1,2 & Su-Le Tian 1,4
Received: 15 June 2020 / Accepted: 15 September 2020 # Springer-Verlag GmbH Germany, part of Springer Nature 2020
Abstract A novel tungsten-doped CeO2 catalyst was fabricated via the sweet potato starch bio-template spread self-combustion (SSC) method to secure a high NH3-SCR activity. The study focuses on the influence of ignition temperature on the physical structure and redox properties of the synthesized catalyst and the catalytic performance of NOx reduction with NH3. These were quantitatively examined by conducting TG-DSC measurements of the starch gel, XRD analysis for the crystallites, SEM and TEM assessments for the morphology of the catalyst, XPS and H2-TPR measurements for the distribution of cerium and tungsten, and NH3-TPD assessments for the acidity of the catalyst. It is found that the ignition temperature shows an important role in the interaction of cerium and tungsten species, and the optimal ignition temperature is 500 °C. The increase of ignition temperature from 150 °C is beneficial to the interactions of species in the catalyst, depresses the formation of WO3, and refines the cubic CeO2 crystallite. The sample ignited at 500 °C shows the biggest BET surface area, the highest surface concentration of Ce species and molar ratio of Ce3+/(Ce3++Ce4+), and the most abundant surface Brønsted acid sites, which are the possible reasons for the superiority of the NH3-SCR activity. With a high GHSV of 200,000 mL (g h)−1 and the optimal ignition temperature, Ce4W2Oz500 can achieve a steadily high NOx reduction of 80% or more at a lowered reduction temperature in the range of 250~500 °C. Keywords Selective catalytic reduction of NOx . Bio-template . Starch . Cerium . Tungsten . Ignition temperature
Highlights • Ignition temperature plays an important role in the interaction of active species in the tungsten-doped CeO2 catalyst synthesized via starch biotemplate spread self-combustion. • An increase of ignition temperature contributes to improving the specific surface area, the defects, and acidity on the surface of catalyst. • Ce4W2Oz ignited at 500 °C exhibits excellent catalytic performance with more than 80% of NOx reduction obtained at 250~500 °C under a high GHSV of 200,000 mL (g h)−1. Responsible editor: Santiago V. Luis Electronic supplementary material The online version of this article (https://doi.org/10.1007/s11356-020-10888-9) contains supplementary material, which is available to authorized users. * Zhi-Bo Xiong [email protected] 1
2
Shanghai Key Laboratory of Multiphase Flow and Heat Transfer in Power Engineering, University of Shanghai for Science and Technology, Shanghai 200093, China
3
China-UK Low Carbon College, Shanghai Jiao Tong University, Shanghai 200240, China
4
Shandong Electric Power Engineering Consulting Institute Corp.
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