Direct coating copper–zinc–aluminum oxalate with H-ZSM-5 to fabricate a highly efficient capsule-structured bifunctional catalyst for dimethyl ether production from syngas

Abstract

This work reports a facile strategy for preparing a highly efficient capsule bifunctional catalyst by direct coating copper–zinc–aluminum oxalate with H-ZSM-5, showing outstanding catalytic properties for dimethyl ether production from syngas.

Implanting Copper−Zinc Nanoparticles into the Matrix of Mesoporous Alumina as a Highly Selective Bifunctional Catalyst for Direct Synthesis of Dimethyl Ether from Syngas

“…To acquire the crystalline structure of these materials, this work used X‐ray diffraction (XRD) to obtain the result. As is shown in Figure , the characteristic diffractions peaks of CuO are located at 35.6, 38.8, 58.3, 61.6, and 66.3° and the XRD peaks at 34.2 and 48.1° corresponding to ZnO phase can be resolved . Furthermore, the characteristic X‐ray diffraction peaks at 66.1° corresponding to m ‐Al 2 O 3 of the CuZn@ m −Al 2 O 3 samples can be resolved, presenting an evidence for the successful coating m ‐Al 2 O 3 .…”

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

“…For another, the presence of Al in the CZA core of CZA@HZSM‐5‐EtOH catalyst can strengthen the CO adsorption, which can also promote CO hydrogenation. Moreover, Al in the core of CZA@HZSM‐5‐EtOH catalyst also endows it with some extra acidic sites . As a result, CZA@HZSM‐5‐EtOH catalyst shows much more acidic sites than CZ@HZSM‐5‐EtOH (Table ), and then the former shows lower methanol content than the latter (4.8 % vs. 7.3 %).…”

“…Because the Cu/ZnO‐based active sites distribute randomly on the surface of solid‐acids, the two tandem reactions (methanol synthesis and the subsequent methanol dehydration) are out of order and take place independently, which results in a low DME selectivity. To address the problem of the open‐structure of bifunctional catalysts for direct synthesis of DME from syngas, core‐shell capsule catalysts were designed . The selectivity of capsule‐structured catalysts obviously is higher than that of the physically mixed catalysts for DME synthesis owing to their closed capsule‐structure.…”

“…In our research group, we previously reported a facile and robust strategy for preparing a highly efficient CZA‐oa@H‐ZSM‐5 capsule‐structured bifunctional catalyst by coating an H‐ZSM‐5 shell on millimetersized copper‐zinc‐aluminum oxalate but not on copper‐zinc‐aluminum oxide via the hydrothermal crystallization process with the subsequent calcination at 500 °C for 5 h in air. It was found that the direct use of CZA‐oa to replace CZA could efficiently inhibited Cu leaching in the coating process, besides turning down the necessity of using a rotary oven for the good coating of the H‐ZSM‐5 shell on the core owing to high hydrophilic property . In addition, the dual‐layer strategies with the formed silicalite‐1 zeolite shell as a protection layer was employed for preparation of CuZnAl@H‐ZSM‐5 capsule catalysts.…”

“…The STD reaction is a tandem reaction, which includes the methanol synthesis process from syngas over the Cu‐based catalysts and methanol dehydration to DME over the solid acid. The STD process was carried out using the core‐shell capsule catalyst composed of millimeter‐sized CZA core and micrometer‐sized HZSM‐5 shell, which is thermodynamically beneficial and more efficient than the conventional DME synthesis by two separated processes . The catalytic performances of the CZA@HZSM‐5‐EtOH, CZA@HZSM‐5‐H 2 O and CZA@HZSM‐5‐SS are shown in the Table and S2.…”