The role of copper oxidation state in Cu/ZnO/Al2O3 catalysts in CO2 hydrogenation and methanol productivity. (September 2019)

• Record Type: Journal Article
• Authors: Dasireddy, Venkata D.B.C.; Likozar, Blaž
• Is Part Of: Renewable energy. Volume 140(2019)
• Page Start: 452
• Page End: 460
• Publication Date: 2019-09
• Subjects: Ultrasonic co-precipitation synthesis -- CO2 activation -- Renewable methanol production -- Cu/ZnO/Al2O3 heterogeneous catalyst materials -- Cu+/Cu0 oxidation state distribution -- Structure-activity relationship; Renewable energy sources -- Periodicals; Power resources -- Periodicals; Énergies renouvelables -- Périodiques; Ressources énergétiques -- Périodiques; 333.794
• DOI: 10.1016/j.renene.2019.03.073
• Languages: English
• ISSNs: 0960-1481

Abstract

Abstract: CO2 hydrogenation was carried out over a series of Cu/ZnO/Al2 O3 catalysts, which were prepared by different synthesis methods (co-precipitation, ultrasound-assisted, sol-gel and solid-state). The applicative physicochemical properties of the materials and their catalytic performance were investigated. Subsequently, the preparation methodology influence on the average Cu particle size, the interactions of metals, the exposed copper phases surface area and the ratio of Cu 0 /Cu +, as well as its specific effect on reactions, were assessed in detail. The ultrasonic synthetic route provided increased basic active sites' number and significant methanol selectivity, compared to the conventional precipitation procedure, while it also improved the dispersion of separate Cu metallic particles, which ultimately changed the intrinsic reactive activity of CuO–ZnO. The trend of apparent CH3 OH productivity rate was consistent with the Cu + /Cu 0 ratio or content as well. The presence of Cu + species at high concentration levels is thus crucial for high methanol selectivity and an extremely low selectivity towards CO at the conventional industrial operating conditions analysed. The dependence of the selective methanol production on the fraction of determined alkaline moieties was found analogous to all catalysts studied. Cu + /Cu 0 oxidation state role and distribution may, therefore, aid in CO2 conversion catalyst design and optimisation. Graphical abstract: Image 1 Highlights: CO2 hydrogenation was done over a series of Cu catalysts, prepared by various synthesis methods. The preparation method influenced on the average Cu particle size and surface area and the ratio of Cu 0 /Cu + . The catalytic activity increases linearly with the copper surface area and the amount of basic site. The trend of CH3 OH productivity rate was consistent with the Cu + /Cu 0 ratio. Cu + /Cu 0 distribution may therefore aid in CO2 conversion catalyst design and optimisation.