Dimethyl ether (DME) is receiving great attention as a clean alternative fuel, owing to the increasing energy demand. Despite tremendous efforts, catalytic synthesis of DME via a high efficient route remains a great challenge. Catalyst design is at the heart of enhancing the catalytic efficiency of DME synthesis. In this paper, we pay close attention to recent advances on the evolution of catalysts for direct dehydration from methanol and for the tandem catalysis from synthesis gas (syngas). The progress in metal deposition mode, support modification, and reaction routes is encouraging in recent years. In addition, significant challenges and future research scope in DME synthesis are focused as well.

The efficient conversion of CO 2 to useful chemicals is a promising way to reduce atmospheric CO 2 concentration and also reduce reliance on fossil-based resources. Although much progress has been made toward the production of basic chemicals, like methanol, through CO 2 hydrogenation, the direct conversion of CO 2 to valueadded aromatics, especially p-xylene (PX), is still a great challenge due to the inert nature of CO 2 and high barrier for C−C coupling. Herein, a bifunctional catalyst composed of Cr 2 O 3 and H-ZSM-5 zeolite (Cr 2 O 3 / H-ZSM-5) was designed for the direct conversion of CO 2 to aromatics. Due to the concertedly synergistic effect between the two components in this bifunctional catalyst, aromatics selectivity of ∼76% at CO 2 conversion of 34.5% was achieved, and there was no catalyst deactivation after 100 h of long-term stability testing. Moreover, a modified bifunctional catalyst Cr 2 O 3

Dimethyl ether (DME) is an industrially important intermediate, as well as a promising clean fuel, but the effective production through traditionally consecutive steps from syngas to methanol and then to DME has been hindered by the poorly organized structure of the conventional physical mixture catalyst. Here, a novel zeolite capsule catalyst possessing a core-shell structure (millimeter-sized core catalyst and micrometer-sized acidic zeolite shell) was proposed initially through a well-designed aluminum migration method using the core catalyst as the aluminum resource and for the first time was applied to accomplish the DME direct synthesis from syngas. The selectivity of the expected DME on this zeolite capsule catalyst strikingly exceeded that of the hybrid catalyst prepared by the traditional mixing method, while maintaining the near-zero formation of the unexpected alkanes byproduct. The preliminary methanol synthesis reaction on the core catalyst and the following DME formation from methanol inside the zeolite shell cooperated concertedly and promoted mutually. This zeolite capsule catalyst with a synergetic confinement core-shell structure can be used to efficiently realize the combination of two and more sequential reactions with many synergistic effects.

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C1 catalysis refers to the conversion of simple carbon-containing compounds, such as carbon monoxide, carbon dioxide, methane, and methanol into high-value-added chemicals, petrochemical intermediates, and clean fuels. Because of the rising oil price and the apprehension of fossil fuel depletion in the future, C1 catalysis has been attracting widespread academic and industrial interest and became one of the most attractive research fields in heterogeneous catalysis. Especially in recent years, benefiting from advanced technology development, precise and controllable material synthesis methods, and powerful computational simulation capabilities, C1 catalysis has achieved remarkable progress in many aspects, including insights into the reaction mechanism, identification of active-site structures, highly efficient catalysts and reaction process, and the reactor designs. This Review highlights the latest developments (from 2012 to 2018) in highly efficient catalyst systems and reaction processes in this field. The content covers the catalytic utilization of the four molecules including carbon monoxide, carbon dioxide, methane, and methanol. The catalytic performances of these highly efficient systems, including activity, selectivity, and stability, are introduced in detail and compared to previously reported catalysts. Furthermore, the established relationships between reactivity and active-site structure are clarified. Finally, current challenges and perspectives for future research are discussed.