Molecular Catalysis for Utilizing CO2 in Fuel Electro-Generation and in Chemical Feedstock

Abstract

Processes for the conversion of CO2 to valuable chemicals are highly desired as a result of the increasing CO2 levels in the atmosphere and the subsequent elevating global temperature. However, CO2 is thermodynamically and kinetically inert to transformation and, therefore, many efforts were made in the last few decades. Reformation/hydrogenation of CO2 is widely used as a means to access valuable products such as acetic acids, CH4, CH3OH, and CO. The electrochemical reduction of CO2 using hetero- and homogeneous catalysts recently attracted much attention. In particular, molecular CO2 reduction catalysts were widely studied using transition-metal complexes modified with various ligands to understand the relationship between various catalytic properties and the coordination spheres above the metal centers. Concurrently, the coupling of CO2 with various electrophiles under homogeneous conditions is also considered an important approach for recycling CO2 as a renewable C-1 substrate in the chemical industry. This review summarizes some recent advances in the conversion of CO2 into valuable chemicals with particular focus on the metal-catalyzed reductive conversion and functionalization of CO2.

Atropisomeric Hydrogen Bonding Control for CO2 Binding and Enhancement of Electrocatalytic Reduction at Iron Porphyrins

“…Iron porphyrins are among the most efficient catalysts for CO 2 electrocatalytic reduction (CO 2 ECR) to CO [16, 19–28] . The simplified mechanism for this reaction can be described in four main steps (Scheme 1) albeit more detailed mechanism with proton‐coupled electron transfer processes have also been proposed.…”

Nickel-phenanthroline Complex Supported on Mesoporous Carbon as a Catalyst for Carboxylation under CO2 Atmosphere

“…Nickel is a transition metal that has been widely used as catalyst for various transformations both in organic and inorganic reactions. In addition, nickel complexes have been widely employed as homogeneous catalyst in carboxylation reaction of various substrates with CO2 [4]. The reaction occurs through formation of a C−C bond to produce a carboxylic acid or its derivatives.…”

Immobilization of molecular catalysts for artificial photosynthesis

“…The concept of storing the solar energy into higherenergy chemicals is the basis of artificial photosynthesis, which is dedicated to producing fuels/high-value chemicals such as H 2 , methane, methanol, or hydrogen peroxide. A number of molecular catalysts have been developed for water splitting [3][4][5][6][7][8][9][10][11][12], CO 2 reduction [13][14][15][16][17][18][19][20][21], and O 2 reduction [22,23]. However, the molecular catalysts in homogeneous solution often suffer from low stability in redox conditions.…”