Continuous synthesis of Cu/ZnO/Al2O3 nanoparticles in a co-precipitation reaction using a silicon based microfluidic reactor. Issue 3 (24th December 2021)

• Record Type: Journal Article
• Authors: Tofighi, Ghazal; Lichtenberg, Henning; Gaur, Abhijeet; Wang, Wu; Wild, Stefan; Herrera Delgado, Karla; Pitter, Stephan; Dittmeyer, Roland; Grunwaldt, Jan-Dierk; Doronkin, Dmitry E.
• Is Part Of: Reaction chemistry & engineering. Volume 7:Issue 3(2022)
• Page Start: 730
• Page End: 740
• Publication Date: 2021-12-24
• Subjects: Reaction mechanisms (Chemistry) -- Periodicals; Chemical engineering -- Periodicals; Chemical engineering; Reaction mechanisms (Chemistry); Periodicals; 547.705
• DOI: 10.1039/d1re00499a
• Languages: English
• ISSNs: 2058-9883

Abstract

Abstract : A microfluidic reactor enabled continuous co-precipitation synthesis of CuO/ZnO/Al2 O3 catalysts for methanol production. Abstract : CuO/ZnO/Al2 O3 catalysts were continuously synthesized in a microfluidic reactor, analyzed by X-ray diffraction (XRD), physisorption (BET), chemisorption, electron microscopy and X-ray absorption spectroscopy (XAS), and tested for methanol synthesis from CO-rich synthesis gas. The results were compared to those obtained from CuO/ZnO and CuO/ZnO/Al2 O3 produced by conventional co-precipitation in a batch reactor. The predominant phase of the aged precursor from microfluidic co-precipitation was identified as zincian malachite. After calcination the microfluidically synthesized catalyst exhibited smaller CuO crystallites, a larger BET surface area, a rather uniform morphology and a homogeneous distribution of Cu and Zn compared to catalysts prepared by batch co-precipitation. H2 -Temperature programmed reduction (TPR) showed that Cu species in CuO/ZnO/Al2 O3 from microfluidic co-precipitation were more easily reducible. In situ Cu and Zn K-edge XAS during the TPR indicated reduction of Cu 2+ to Cu 0 between 150 °C and 240 °C, without detectable reduction of Zn. N2 O pulse chemisorption evidenced an enlarged Cu surface area of the nanoparticles from the microfluidic synthesis. Based on activity tests in methanol synthesis, at 250 °C the microfluidically synthesized Cu/ZnO/Al2 O3 catalysts showed better performance than the catalyst from batch preparation when 1 mol% CO2 was present in the synthesis gas. Dimethyl ether formed as a side product. As the microreactor is specially designed for high X-ray transmission with a thin Si/glass observation window, this study opens interesting perspectives for investigating the formation of catalyst precursors at the early stage of precipitation in future.