Progress and Perspective of Electrocatalytic CO₂ Reduction for Renewable Carbonaceous Fuels and Chemicals

Abstract

The worldwide unrestrained emission of carbon dioxide (CO2) has caused serious environmental pollution and climate change issues. For the sustainable development of human civilization, it is very desirable to convert CO2 to renewable fuels through clean and economical chemical processes. Recently, electrocatalytic CO2 conversion is regarded as a prospective pathway for the recycling of carbon resource and the generation of sustainable fuels. In this review, recent research advances in electrocatalytic CO2 reduction are summarized from both experimental and theoretical aspects. The referred electrocatalysts are divided into different classes, including metal–organic complexes, metals, metal alloys, inorganic metal compounds and carbon‐based metal‐free nanomaterials. Moreover, the selective formation processes of different reductive products, such as formic acid/formate (HCOOH/HCOO−), monoxide carbon (CO), formaldehyde (HCHO), methane (CH4), ethylene (C2H4), methanol (CH3OH), ethanol (CH3CH2OH), etc. are introduced in detail, respectively. Owing to the limited energy efficiency, unmanageable selectivity, low stability, and indeterminate mechanisms of electrocatalytic CO2 reduction, there are still many tough challenges need to be addressed. In view of this, the current research trends to overcome these obstacles in CO2 electroreduction field are summarized. We expect that this review will provide new insights into the further technique development and practical applications of CO2 electroreduction.

Highly Active, Durable Ultrathin MoTe2 Layers for the Electroreduction of CO2 to CH4

“…With the further increase in the negative potential, the maximum FE (FE max ) of 83 ± 3% at −1.0 V RHE was achieved with ≈15% of CO and ≈5% of H 2 . This change in activity can be attributed to the following reasons: (i) at different applied potentials, the deviation with respect to the equilibrium potential of the target product will impact the reaction pathway of CO 2 electroreduction and thereby led to the variation of the reduction products, which in turn results in a change of the FE for the target product; (ii) the hydrogen evolution reaction (HER) as the competing reaction also induces the change in efficiency. The total FEs consistently reached 90%–103% at all potentials where methane was selectively produced, indicating that the electroreduction of CO 2 is more favorable compared to the HER.…”

Recent Progress in the Theoretical Investigation of Electrocatalytic Reduction of CO2

“…When the product is generated during the electrochemical experiments at Table 1. [14,19] www.advancedsciencenews.com www.advtheorysimul.com a detectable amount or the current starts to be measured from 0, the applied voltage on the electrode is usually apart from the thermodynamically determined standard potential. [14,19] www.advancedsciencenews.com www.advtheorysimul.com a detectable amount or the current starts to be measured from 0, the applied voltage on the electrode is usually apart from the thermodynamically determined standard potential.…”

Looking Back and Looking Ahead in Electrochemical Reduction of CO2

“…All the given potentials in the above equations are referred to a standard hydrogen electrode (SHE at pH 7) . Because the required thermodynamic potentials are only slightly different from each other, the product selectivity is a second major difficulty in ECRP . In addition, undesirable hydrogen evolution reaction (HER) is often favored and thus competitive with the CO 2 reduction.…”

“…In addition, undesirable hydrogen evolution reaction (HER) is often favored and thus competitive with the CO 2 reduction. Therefore, the key factor in the process is development of electrocatalyst to efficiently promote the desired reaction for target product . Tremendous research efforts have focused on the rational design and synthesis of electrocatalyst that could convert CO 2 at high catalytic current density with minimum overpotential while HER has to be suppressed to enhance the selectivity toward the desired products .…”