Highly Effective Pd/MgO/γ-Al₂O₃ Catalysts for CO Oxidative Coupling to Dimethyl Oxalate: The Effect of MgO Coating on γ-Al₂O₃

Abstract

The support of MgO/γ-Al2O3 was initially prepared by a multiple impregnation method and Pd was placed on the surface of the MgO/γ-Al2O3 support via incipient wetness impregnation. Pd/MgO/γ-Al2O3 (Pd/MAO) catalysts were systematically characterized by X-ray diffraction (XRD), Brunauer–Emmett–Teller (BET), CO2-temperature-programmed desorption (TPD), transmission electron microscopy (TEM), CO-Fourier transform infrared (CO-FTIR), and X-ray photoelectron spectroscopy (XPS) and tested in the CO oxidative coupling to dimethyl oxalate (DMO) reaction. Compared to Pd/γ-Al2O3, the catalytic activities of the Pd/MAO catalysts improved significantly. The Pd/MAO catalyst with a 30% mass ratio of Mg to γ-Al2O3 delivers 3 times higher STY of DMO than that of Pd/γ-Al2O3. It has been demonstrated that MgO covered γ-Al2O3 layer-by-layer forming MAO supports, which can increase surface basicity and the interaction between Pd particles and the MAO supports. Moreover, the relationship between metal and support interaction and catalytic performance was discussed.

An overview of mono‐ethylene glycol synthesis via CO coupling reaction: Catalysts, kinetics, and reaction pathways

“…In a recent study, MgO was coated on the γ‐Al 2 O 3 surface, and over this support, Pd was impregnated to study the CO oxidative coupling reaction. [ 78 ] The MgO coating was found to enhance the basicity of the catalyst, which enhanced the selectivity of the DMO. The catalyst also shows stronger interaction between the MgO layer and Pd, giving smaller Pd nanoparticles and high activity (48.3% CO conversion and 94.4% DMO selectivity) for the CO oxidative coupling reaction.…”

Tuning the Phase Structure of ZnTiO3 Support to Promote the Catalytic Activity of Pd/ZnTiO3 Catalyst for the CO Oxidative Coupling to Dimethyl Oxalate

“…Till now, the production of DMO is mainly through the reaction of CO oxidative coupling with methyl nitrite (CH 3 ONO; MN): 2 CO+2 CH 3 ONO→(COOCH 3 ) 2 +2 NO. To the best of our knowledge, CO oxidative coupling to DMO is a crucial step of coal to ethylene glycol [2] . Such an oxidative coupling process could successfully achieve the transformation of inorganic C 1 to organic C 2 .…”

“…Pd‐Based heterogeneous nanocatalysts, such as Pd/α‐Al 2 O 3 , [3] Pd/Mg‐ZnO, [4] Pd/AlOOH/Al‐Fiber, [5] Pd/ZnTi‐LDH, [6] Pd/MgO/γ‐Al 2 O 3 , [2] and so forth, has been intelligently designed and utilized to catalyze CO oxidative coupling to DMO. These investigations proclaim that the activity of the Pd‐based catalyst is closely related to surface acidity and alkalinity of the support, the morphology of the support, type of promoter, and electronic structure of Pd active species.…”

“…To the best of our knowledge, CO oxidative coupling to DMO is a crucial step of coal to ethylene glycol. [2] Such an oxidative coupling process could successfully achieve the transformation of inorganic C 1 to organic C 2 .…”

Theoretical exploration of the origin of selectivity for the oxidative carbonylation reaction catalyzed by a single Pd atom embedded on graphene

“…[1][2][3][4] This reaction can give dimethyl carbonate (DMC) or dimethyl oxalate (DMO), as shown in eqn (1) and (2). Over the past decades, many Pd-based catalysts employing various catalytic supports have been reported to be effective for the reaction, including carbon materials, [5][6][7] metal oxides, [8][9][10][11] and porous materials. [12][13][14][15][16][17][18][19] For the rational development of related catalysts, it is necessary to gain molecular insight into the reaction mechanisms and to understand the relationship between the selectivity and the structures of catalysts.…”