Perspective on CO2 Hydrogenation for Dimethyl Ether Economy

Abstract

The CO2 hydrogenation to dimethyl ether (DME) is a potentially promising process for efficiently utilizing CO2 as a renewable and cheap carbon resource. Currently, the one-step heterogeneous catalytic conversion of CO2 to value-added chemicals exhibits higher efficiency than photocatalytic or electrocatalytic routes. However, typical catalysts for the one-step CO2 hydrogenation to DME still suffer from the deficient space–time yield and stability in industrial demonstrations/applications. In this perspective, the recent development of the one-step CO2 hydrogenation to DME is focused on different catalytic systems by examining the reported experimental results and the reaction mechanism including the catalytic nature of active sites, activation modes and of CO2 molecules under relevant conditions; surface intermediates are comparatively analyzed and discussed. In addition to the more traditional Cu-based, Pd-based, and oxide-derived bifunctional catalysts, a further emphasis is given to the characteristics of the recently emerged In2O3-based bifunctional catalysts for the one-step conversion of CO2 to DME. Moreover, GaN itself, as a bifunctional catalyst, shows over 90% DME selectivity and a reasonably high activity for one-step CO2 hydrogenation, and the direct hydrogenation of CO2 via the unique non-methanol intermediate mechanism is highlighted as an important illustration for exploring new catalytic systems. With these analyses and current understandings, the research directions in the aspects of catalysis and DME economy are suggested for the further development of one-step DME synthesis from CO2 hydrogenation.

Zn Redistribution and Volatility in ZnZrOx Catalysts for CO2 Hydrogenation

“…Methanol STY values ranging from 2.0 to 12.5 mol methanol kg –1 h –1 were achieved under the range of operating conditions investigated in this work. In the literature, values up to 16 mol methanol kg –1 h –1 can be found for these ZnZrO x catalysts; values ranging from 0.9 to 16 mol methanol kg –1 h –1 were reported by Liu and Liu in their review on CuZn-based catalysts and similar values up to 10 mol methanol kg –1 h –1 were reported for In 2 O 3 /ZrO 2 catalysts . However, a direct comparison of measurements reported herein to these literature values is difficult because of the different conditions tested in each case, most of the time with significantly higher pressure than that used here.…”

Advances in CO2 recycle to alcohols and ethers through hydrogenation

“…The Δ H for this exothermic reaction is ‐122 kJ/mol, 48 or ‐2.64 MJ/kg. The procedure is more intricate than methanol synthesis and encompasses several reaction steps, contingent on the particular catalyst and reaction conditions utilized.…”

“…The enthalpy change (ΔH) for this exothermic reaction is ‐122 kJ/mol, 48 equivalent to ‐2.64 MJ/kg. Typically, the process requires high‐pressure conditions and the use of an appropriate catalyst, such as copper‐based catalysts, to improve the efficiency of the reaction.…”

“…Works such as those in Refs. [29,30,48,77] provide reviews on the production of DME through heterogeneously catalyzed CO 2 hydrogenation processes. Several catalysts have been developed to facilitate the direct hydrogenation of CO 2 to DME, incorporating cascade catalysis involving methanol synthesis and methanol condensation to DME over a supported copper catalyst.…”

Improving Net Energy Efficiency of Dimethyl Ether Production Process by Methanol Dehydration

“…The increasing global environmental pollution and energy supply issues have drawn attention to dimethyl ether (DME), a multisource, multi-purpose product [1]. Syngas, which is created from natural gas, coal, or biomass, can be used to make DME [2]. So, Dimethyl Ether (DME, H3COCH3) is regarded as a meaningful alternative fuel as it has a comparably high energy density [3], can easily be stored on vehicles, can be produced via different renewable reaction side [8].…”