Methanol Synthesis from CO2: A Review of the Latest Developments in Heterogeneous Catalysis

Abstract

Technological approaches which enable the effective utilization of CO₂ for manufacturing value-added chemicals and fuels can help to solve environmental problems derived from large CO₂ emissions associated with the use of fossil fuels. One of the most interesting products that can be synthesized from CO₂ is methanol, since it is an industrial commodity used in several chemical products and also an efficient transportation fuel. In this review, we highlight the recent advances in the development of heterogeneous catalysts and processes for the direct hydrogenation of CO₂ to methanol. The main efforts focused on the improvement of conventional Cu/ZnO based catalysts and the development of new catalytic systems targeting the specific needs for CO₂ to methanol reactions (unfavourable thermodynamics, production of high amount of water and high methanol selectivity under high or full CO₂ conversion). Major studies on the development of active and selective catalysts based on thermodynamics, mechanisms, nano-synthesis and catalyst design (active phase, promoters, supports, etc.) are highlighted in this review. Finally, a summary concerning future perspectives on the research and development of efficient heterogeneous catalysts for methanol synthesis from CO₂ will be presented.

Keywords: CO2; catalysts; hydrogenation; methanol; review.

Figure 1

Pathways of methanol synthesis from CO₂ hydrogenation over Cu-based catalysts (adapted from References [58,59]).

Figure 2

Microscopy images of the materials obtained at different stages in the course of the preparation of Cu/ZnO/Al₂O₃ catalysts.

Figure 3

Reaction network on Cu–ZnO/ZrO₂ catalysts [79].

Figure 4

Reaction network to methanol on Cu/ZrO₂ catalysts (adapted from Reference [90]).

Figure 5

Representation of the bifunctional Cu and defective In₂O₃ sites operating in methanol synthesis from CO₂ on Cu/ZrO₂–In₂O₃ catalysts [92].

Figure 6

Intermediate species of CO₂ adsorption and hydrogenation on Cu/CeO₂ catalysts (adapted from Reference [95]).

Figure 7

Site (oxygen vacancy) for methanol synthesis from CO₂ hydrogenation on In₂O₃ (110). Reprinted with permission from Reference 112). Copyright (2019) American Chemical Society.