Improved Preparation of Cu/Zn‐Based Catalysts by Well‐Defined Conditions of Co‐Precipitation and Aging

Abstract

In order to enable science-and knowledge-based adaptation of catalyst materials to new demands, e.g., methanol synthesis from CO 2 , a modified method to prepare Cu/Zn-based catalysts based on the strict consecutive execution of co-precipitation and aging is investigated. By successfully stabilizing the initial co-precipitate, two mixing regimes are revealed: regarding slow mixing, the particle size of the co-precipitate decreases with increasing volume flow. By contrast, co-precipitation is no longer influenced by mixing for sufficiently high volume flows. While aging can be accelerated by forming smaller aggregates in the co-precipitation, the final state is found to be defined by thermodynamic equilibrium alone. Furthermore, the microstructure of the final catalyst was influenced and the performance in direct dimethyl ether synthesis was improved by adjusting the mixing in the co-precipitation. We believe that the approach could be scaled-up to industrial production rates and, hence, is promising to make methanol synthesis from CO 2 more effective and sustainable.

Dynamics of the Cu/CeO2catalyst during methanol steam reforming

“…S5a and b †). 58,59 Likewise, in situ CO-DRIFTS of 20%Cu/Al 2 O 3 -DP shows an absorption peak at 2138 cm −1 absent for 20%Cu/Al 2 O 3 -CP (Fig. S5c and d †).…”

Is Direct DME Synthesis Superior to Methanol Production in Carbon Dioxide Valorization? From Thermodynamic Predictions to Experimental Confirmation

“…However, it cannot withstand the water-rich conditions of CtD (Eq ). Apparently, Lewis acidic materials like γ-Al 2 O 3 tend to be more severely affected than Brønsted acidic materials. , In this regard, zeolites are the focus of research. ,,,,,− But since zeolites are used in hydrocracking as well, overreactions, like the formation of methane or higher carbons, are to be expected as side products . A new class of catalysts for the MtD reaction are Keggin-like heteropoly acid (HPA)-coated carrier materials (e.g., tungstosilicic acid).…”

“…Yet, a CO 2 -rich or pure CO 2 feed gas makes CZA less attractive due to water poisoning. A promising alternative is found in the ternary copper/zinc oxide/zirconia (CZZ) system. ,− The commonly used dehydration catalyst for the MtD process in industry is γ-Al 2 O 3 . However, it cannot withstand the water-rich conditions of CtD (Eq ).…”

Design of Cu/ZnO/Al2O3catalysts with a rich Cu–ZnO interface for enhanced CO2hydrogenation to methanol using zinc-malachite as the precursor

“…21 Due to the chemical memory effect, the arrangement of Cu and Zn atoms defined by the zinc-malachite lattice will be retained in the calcination process. 25 The existence of single CuO and ZnO is inhibited after the calcination of the precursor, which promotes the formation of Cu–ZnO interfaces. 21 Hence, the use of zinc-malachite as the precursor to construct Cu/ZnO/Al 2 O 3 catalysts with rich Cu–ZnO interfaces is promising.…”