Insight into the effect of surface structure for Pd catalyst on CO oxidative coupling to dimethyl oxalate

Recent advances in the routes and catalysts for ethanol synthesis from syngas

Ethanol, as one of the important bulk chemicals, is widely used in modern society. It can be produced by fermentation of sugar, petroleum refining, or conversion of syngas (CO/H₂). Among these approaches, conversion of syngas to ethanol (STE) is the most environmentally friendly and economical process. Although considerable progress has been made in STE conversion, control of CO activation and C-C growth remains a great challenge. This review highlights recent advances in the routes and catalysts employed in STE technology. The catalyst designs and pathway designs are summarized and analysed for the direct and indirect STE routes, respectively. In the direct STE routes (i.e., one-step synthesis of ethanol from syngas), modified catalysts of methanol synthesis, modified catalysts of Fischer-Tropsch synthesis, Mo-based catalysts, noble metal catalysts and multifunctional catalysts are systematically reviewed based on their catalyst designs. Further, in the indirect STE routes (i.e., multi-step processes for ethanol synthesis from syngas via methanol/dimethyl ether as intermediates), carbonylation of methanol/dimethyl ether followed by hydrogenation, and coupling of methanol with CO to form dimethyl oxalate followed by hydrogenation, are outlined according to their pathway designs. The goal of this review is to provide a comprehensive perspective on STE technology and inspire the invention of new catalysts and pathway designs in the near future.

A predicted new catalyst to replace noble metal Pd for CO oxidative coupling to DMO

The reaction mechanisms of CO oxidative coupling to dimethyl oxalate (DMO) on different β-Mo2C(001) based catalysts have been studied by the density functional theory (DFT) method.

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

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.