Issue 13, 2020

Catalytic reduction of CO2 into fuels and fine chemicals

Abstract

With the progressive increase in atmospheric CO2 over the years and owing to its potential environmental threat, researchers have focused their attention on the fruitful utilization of CO2 into value-added chemicals and feedstocks. Although CO2 conversion reactions are intensively studied through several electrochemical, photochemical and photo-electrochemical pathways, chemical reduction of CO2 is more challenging to achieve due to the involvement of breaking of high energy C[double bond, length as m-dash]O bonds without any applied potential together with the accomplishment of green chemistry perspectives. Considerable progress in the chemical reduction of CO2 in the presence of reducing agents over homogeneous and heterogeneous catalysts has been achieved over the years. However, this technology has several pitfalls to overcome before it can be utilized in large scale industrial processes. We show here the recent progress in CO2 reduction to essential fuels [CO, CH3OH, CH3CH2OH, HCO2H, CH4, dimethylether (DME), dimethylcarbonate (DMC) and lower hydrocarbons] as well as valuable chemicals via nucleophilic addition reactions. We also emphasize the direct conversion of CO2 from ultra-diluted sources like ambient air as a possible roadmap to solve carbon emission problems from the real world. The entire discussion is divided into two parts where in the first part we summarize several homogeneous catalytic processes involving the nucleophilic addition of CO2, resulting in C–C and C–H bond formation leading to the synthesis of 2-oxazolidinones, aminals, terminal carboxylated products and indolelactone derivatives that are potentially sound for the pharmaceutical industry. Other reduction products, such as methane, methanol, and methoxides, are also listed using Frustrated Lewis Pairs (FLP) as catalysts. The second part extensively highlights heterogeneous catalysts to reduce CO2 with H2. However, significant efforts are still needed to develop active, selective and stable catalysts on a pilot plant scale by judicial consideration of the thermodynamics and kinetics of the reactions. CO2 reduction can proceed over a range of immobilized metallic nanoparticles on inorganic supports (CeO2, Al2O3, TiO2etc.) and nanostructured porous frameworks (zeolites, porous polymers, mesoporous silica). Thus, thorough investigation on the reaction mechanism of the overall process involving different active sites is necessary. Primarily, this review brings together the major advancements made in the CO2 reduction processes together with a focus on the utility and challenges in achieving the activation of the CO2 molecule.

Graphical abstract: Catalytic reduction of CO2 into fuels and fine chemicals

Article information

Article type
Critical Review
Submitted
27 Mar 2020
Accepted
18 May 2020
First published
17 Jun 2020

Green Chem., 2020,22, 4002-4033

Catalytic reduction of CO2 into fuels and fine chemicals

A. Modak, P. Bhanja, S. Dutta, B. Chowdhury and A. Bhaumik, Green Chem., 2020, 22, 4002 DOI: 10.1039/D0GC01092H

To request permission to reproduce material from this article, please go to the Copyright Clearance Center request page.

If you are an author contributing to an RSC publication, you do not need to request permission provided correct acknowledgement is given.

If you are the author of this article, you do not need to request permission to reproduce figures and diagrams provided correct acknowledgement is given. If you want to reproduce the whole article in a third-party publication (excluding your thesis/dissertation for which permission is not required) please go to the Copyright Clearance Center request page.

Read more about how to correctly acknowledge RSC content.

Social activity

Spotlight

Advertisements