Effect of Copper Precursors to the Activity for Dimethyl Ether Synthesis from Syngas over Cu–ZnO/γ-Al₂O₃ Bifunctional Catalysts

Abstract

The effect of precursors, such as copper nitrate, acetate, and chloride, on the bifunctional CuÀZnO/γ-Al 2 O 3 catalysts was investigated for the direct dimethyl ether (DME) synthesis from syngas. The catalysts were characterized by measuring the reducibility and the surface area of metallic copper, together with their acidity. The well-dispersed copper particles with a high reducibility as well as a large amount of weak acidic sites on the bifunctional CuÀZnO/γ-Al 2 O 3 catalysts, prepared from a copper acetate precursor, are responsible for its high catalytic activity. The quantity of the acidic sites is a more crucial factor for obtaining a high DME yield than the surface area of metallic copper on the bifunctional catalyst.

One-pot synthesis of mesoporous Cu–γ-Al2O3 as bifunctional catalyst for direct dimethyl ether synthesis

“…At higher temperature, more hydrocarbons were detected. Compared to the published study on a related catalyst system [24], in which a selectivity to methanol exceeding 30% in the best case was observed, no methanol was detected here at all investigated temperatures. Methanol selectivity is most probably governed by the balance between CO-hydrogenation functionality and acid functionality, which need to be optimized to achieve the desired performance.…”

“…Compared to the conventional wet impregnation method, the mesoporous alumina supported metals by one-pot method were reported to have high-quality mesostructures that exhibit strong metal-support interactions and a homogeneous distribution of active sites [23]. A bifunctional catalyst for one-step DME synthesis can be obtained by loading copper on the surface of c-Al 2 O 3 using the conventional impregnation method or the co-precipitation and deposition method reported by Baek et al [24]. In order to get a high dispersion of copper, we therefore extended the one-pot method described above for the synthesis of mesoporous c-Al 2 O 3 supported copper (Cu/cAl 2 O 3 ), and explored its application as bifunctional catalyst for one-step DME synthesis from synthesis gas after reduction of the copper species to result in a supported catalyst Cu/ c-Al 2 O 3 .…”

Cu/ZnO Catalysts Derived from Bimetallic Metal–Organic Framework for Dimethyl Ether Synthesis from Syngas with Enhanced Selectivity and Stability

“…In the literature, the deactivation of Cu/ZnO‐based catalysts has mainly been related to the sintering of Cu. [ 12b,14a,23 ] Small Cu particles are easy to aggregate into large particles via Ostwald ripening or particle migration, which further leads to the reduced methanol formation rate. [ 24 ] In this context, the 40‐h continuous performances of STD reaction over CZ‐350/A and CZ‐CP/A were monitored; the results of which are displayed in Figure 3C,D in terms of CO conversion and DME selectivity, respectively.…”

Ethanol as a Binder to Fabricate a Highly‐Efficient Capsule‐Structured CuO−ZnO−Al2O3@HZSM‐5 Catalyst for Direct Production of Dimethyl Ether from Syngas

“…Apart from the aforementioned hybrid catalysts, the supported bifunctional catalysts were also frequently used in the STD reactions . The supported catalyst can be produced by the coprecipitation, impregnation, sol‐gel, and wet‐chemical ways . The character and performance of the supported catalysts in the STD reaction strongly depend on their synthesis method.…”

“…[2,[51][52][53][54][55][56][57][58][59][60] The supported catalyst can be produced by the coprecipitation, impregnation, sol-gel, and wet-chemical ways. [61][62][63][64][65][66][67][68][69][70] The character and performance of the supported catalysts in the STD reaction strongly depend on their synthesis method. In the last few years, new synthetic technologies such as ultrasound-assisted method and physical sputtering were also employed to prepare the supported bifunctional catalysts.…”