Enhanced Stability of Spatially Confined Copper Nanoparticles in an Ordered Mesoporous Alumina for Dimethyl Ether Synthesis from Syngas

Abstract

A spatial confinement effect of copper nanoparticles in an ordered mesoporous γ-Al2O3, which is synthesized by an evaporation induced self-assembly (EISA) method, was investigated to verify the enhanced catalytic activity and stability with less aggregation of copper crystallites during direct synthesis of dimethyl ether (DME) from syngas. The surface acidity of the mesoporous Al2O3 and the metallic copper surface area significantly altered catalytic activity and stability. The ordered mesopore structures of Al2O3 were effective to suppress the aggregation of copper nanoparticles even under reductive CO hydrogenation conditions through the spatial confinement effect of the ordered mesopores of Al2O3 as well as the formation of strongly interacted copper nanoparticles with the mesoporous Al2O3 surfaces by partial formation of the interfacial CuAl2O4 species. The aggregation of copper nanoparticles on the bifunctional Cu/meso-Al2O3 having an ordered mesoporous structure was effectively suppressed due to the partial formation of the thermally stable spinel copper aluminate phases, which can further generate new acid sites for dehydration of methanol intermediate to DME.

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

“…Figure shows the isotherms and the pore size distribution regarding mesopores, and the quantitative data are listed in Table . The mesoporous structures of the solid acid m ‐Al 2 O 3 and CuZn@ m −Al 2 O 3 catalysts were confirmed by the typical type IV adsorption‐desorption isotherms . However, the typical type IV adsorption‐desorption isotherm cannot be observed on the CuZn/ m −Al 2 O 3 catalyst although the m ‐Al 2 O 3 support has a typical mesoporous structure, might be ascribed to the blockage of mesopores of m ‐Al 2 O 3 by a large amount of CuZn nanoparticles.…”

“…The catalytic performance of CuZn@ m −Al 2 O 3 and CuZn/ m −Al 2 O 3 is presented in Table and S1. The CuZn@ m −Al 2 O 3 catalyst shows slightly higher TOF than CuZn/ m −Al 2 O 3 for direct synthesis of DME from syngas, ascribed to the stronger promotion of ZnO by the intensified Cu−ZnO interaction …”

“…This can be ascribed to the unique implanting‐type structure of CuZn@ m −Al 2 O 3 catalyst and the higher Al content (60 % vs. 10 %). Moreover, CuZn@ m −Al 2 O 3 catalyst shows lower methane content than CuZn/ m −Al 2 O 3 catalyst, originating from the suppressed formation of methane or the promoted conversion of the as‐formed methane to methanol by intensified Cu−ZnO interaction. For another, we compared the catalytic performance of the implanted single component catalysts (Cu@ m −Al 2 O 3 and Zn@ m −Al 2 O 3 ) to present a further insight.…”

Supported Porous Nanomaterials as Efficient Heterogeneous Catalysts for CO2 Fixation Reactions

“…Bae et al. has reported Cu NPs supported over ordered mesoporous alumina material through an evaporation‐induced self‐assembly (EISA) method as an efficient catalyst for the synthesis of DME from syngas. The strong interaction of Cu NPs with the alumina surface, due to the formation of the interfacial CuAl 2 O 4 species, could be responsible for higher DME selectivity.…”

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

“…[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.…”