The Cu–ZnO synergy in methanol synthesis from CO2, Part 2: Origin of the methanol and CO selectivities explained by experimental studies and a sphere contact quantification model in randomly packed binary mixtures on Cu–ZnO coprecipitate catalysts

• Published in: Journal of catalysis Vol. 330; pp. 533 - 544
• Main Authors: Tisseraud, Céline, Comminges, Clément, Belin, Thomas, Ahouari, Hania, Soualah, Ahcène, Pouilloux, Yannick, Le Valant, Anthony
• Format: Journal Article
• Language: English
• Published: San Diego Elsevier Inc 01-10-2015; Elsevier BV; Elsevier
• Subjects: Carbon monoxide; Catalysts; Chemical precipitation; Chemical Sciences; Chemical synthesis; CO2 valorization; Copper; Core–shell structures; Cu–ZnO synergy; Hydrogen spillover; Methane biosynthesis; Methanol synthesis; Selectivity; Sphere contact quantification model; Structure–activity relationships; Zinc oxide; Sphere contact quantification model; Methanol synthesis; Cu–ZnO synergy; Zinc oxide; Selectivity; Core–shell structures; Copper; CO2 valorization; Structure–activity relationships; Hydrogen spillover
• ISSN: 0021-9517; 1090-2694
• DOI: 10.1016/j.jcat.2015.04.035

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•The MeOH and CO selectivities are markedly influenced by the catalyst composition.•Two distinct catalytic sites are evidenced: ZnOx for MeOH and ZnO for CO.•Hydrogen spills over the two catalytic sites through Cu–ZnO contact points.•A predictive model for contact quantification in coprecipitates was developed.•Efficient CO-free methanol synthesis core–shell catalysts were developed.
Methanol synthesis from CO2 over industrial catalysts suffers from a lack of selectivity, since large amounts of CO are formed as by-product. The understanding of the Cu–ZnO synergy in the creation of the active sites for methanol and CO formation is therefore a key for the development of catalysts for CO-free methanol synthesis. Cu–ZnO coprecipitate catalysts with variable compositions were employed as a tool for correlating physical to catalytic properties. Hydrogen spillover on two distinct active sites was demonstrated to be the result of Cu–ZnO contacts. The latter were quantified by using a mathematical model for sphere contact quantification in randomly packed binary mixtures. Theoretical calculations were in total agreement with experimental results. This allowed the rational design of catalysts based on core–shell structures for efficient CO-free methanol synthesis.