The effect of lanthanum in Cu/La(-Zr)-Si oxide catalysts for aqueous ethanol conversion into 1,3-butadiene

• Published in: Molecular catalysis 2022-01, Vol.518, p.112096, Article 112096
• Main Authors: Kyriienko, Pavlo I., Larina, Olga V., Balakin, Dmytro Yu, Vorokhta, Mykhailo, Khalakhan, Ivan, Sergiienko, Sergii A., Soloviev, Sergiy O., Orlyk, Svitlana M.
• Format: Article
• Language: English
• Subjects: 1,3-Butadiene; Copper; Ethanol; Lanthanum; NAP-XPS; Zirconium oxide
• ISSN: 2468-8231; 2468-8231
• DOI: 10.1016/j.mcat.2021.112096

•High (≥65%) 1,3-butadiene selectivity is achieved over Cu/La(-Zr)-Si catalysts.•Modification with La increases Cu/Zr-Si activity in aqueous ethanol conversion.•The effect is explained by formation of base sites being tolerant to H2O action.•NAP-XPS is used to elucidate active catalyst components under reaction conditions. This paper presents the results of an investigation of three (Cu/La-Si and Cu/Zr-Si) and four (Cu/La-Zr-Si) component oxide systems in aqueous ethanol conversion into 1,3-butadiene, with special accent to the effect of lanthanum in the catalyst composition. The catalysts were characterized by HRTEM, SEM, DR UV−vis, in situ near ambient pressure X-ray photoelectron spectroscopy (NAP-XPS), FTIR with pyridine, and TPD-CO2. The high (≥65%) 1,3-butadiene selectivity is achieved during the conversion of both rectified and aqueous ethanol over the studied catalysts. Catalyst activity of the four-component oxide systems depends on an introduction order of the components, which determines acid-base characteristics of the surface. A modification of the Cu/Zr-Si catalyst with lanthanum increases their activity in aqueous ethanol conversion into 1,3-butadiene. The positive effect of lanthanum addition into Cu/Zr-Si catalyst can be explained by the formation of lanthanum-containing base sites like [La–Ö–Si] and [La–Ö–H] being tolerant to the action of water. The differences in the interaction of reaction intermediates with surface Zr- and La-containing sites are found out by C 1 s NAP-XPS measurements, and the effect of H2O on adsorption of carbon coke, ethoxy species and acetaldehyde over the catalyst surface is shown. [Display omitted]