Au/Ce 0.5 Zr 0.5 O 2 catalysts for hydrogen production via partial oxidation of methanol
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Au/Ce0.5Zr0.5O2 catalysts for hydrogen production via partial oxidation of methanol E. Hernández1 · J. A. Wang1 · M. A. Valenzuela1 · L. F. Chen1 · U. Arellano2 · A. K. Dalai3 Received: 12 June 2020 / Accepted: 24 August 2020 © Akadémiai Kiadó, Budapest, Hungary 2020
Abstract Effects of Z rO2 addition to the Au/CeO2 and the pretreatment methods of the catalysts on the partial oxidation of methanol (POM) were investigated. Z rO2 addition to Au/CeO2 catalyst led to (i) formation of a Ce0.5Zr0.5O2 solid solution; (ii) enhancement of lattice oxygen reducibility of the Ce0.5Zr0.5O2 support; and (iii) formation of surface Auδ+ (δ = 1 or 3) species coexisting with Au0 nanoparticles. Catalytic evaluation showed that the highest hydrogen selectivity was achieved over Au/Ce0.5Zr0.5O2 at 270 °C. The reductive pretreatment could improve the hydrogen selectivity and methanol conversion as well. At higher reaction temperature A uδ+ clusters in Au/ Ce0.5Zr0.5O2 catalyst activated the O‒H bond in the adsorbed C H3‒Oδ−‒Hδ+ due to δ+ δ− δ+ the interaction between A u and O ‒H of methanol that favors the release of H + proton, and thus benefits the H 2 selectivity enhancement. Some oxygen vacancies in the catalysts evidenced by XPS analysis participated in the formation of active surface oxygen species that promoted CO oxidation to CO2 on Au0 nanoparticles A reaction mechanism of POM involving in the methanol surface adsorption on Auδ+ species, O‒H bond activation, and CO oxidation on Au0 nanoparticles and oxygen defects was proposed.
Electronic supplementary material The online version of this article (https://doi.org/10.1007/s1114 4-020-01850-4) contains supplementary material, which is available to authorized users. * J. A. Wang [email protected]; [email protected] 1
Laboratorio de Catálisis Y Materiales, ESIQIE, Instituto Politécnico Nacional, Col. Zacatenco, 07738 Mexico City, Mexico
2
Departamento de Química, Universidad Autónoma Metropolitana-Iztapalapa, Av. San Rafael Atlixco No. 186, Iztapalapa, Mexico City, Mexico
3
Department of Chemical and Biological Engineering, University of Saskatchewan, Saskatoon, SK S7N 5A9, Canada
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Reaction Kinetics, Mechanisms and Catalysis
Graphic abstract
Keywords Nanogold · Au/CeO2 · Au/ce0.5zr0.5O2 · Partial oxidation of methanol · Hydrogen production Abbreviations POM Partial oxidation of methanol XRD X-ray diffraction TPR Temperature-programmed reduction BET Brunauer–Emmett–Teller method FTIR Fourier transform infrared GHSV Gas hourly space velocity FID Flame ionization detector TCD Thermal conductivity detector
Introduction In the last decades, hydrogen received increasing attention from both scientific investigation and industrial sectors because of its important role in the global-concerned issues of environmental pollution control, climate change and energy innovation. Hydrogen has a wide spectrum of applications in fuel cell technology and petrochemical industries, and many other areas [1, 2]. There are a numb
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