Potential Link between Cu Surface and Selective CO₂ Electroreduction: Perspective on Future Electrocatalyst Designs

Abstract

Electrochemical reduction of carbon dioxide (CO2RR) product distribution has been identified to be dependent on various surface factors, including the Cu facet, morphology, chemical states, doping, etc., which can alter the binding strength of key intermediates such as *CO and *OCCO during reduction. Therefore, in‐depth knowledge of the Cu catalyst surface and identification of the active species under reaction conditions aid in designing efficient Cu‐based electrocatalysts. This progress report categorizes various Cu‐based electrocatalysts into four main groups, namely metallic Cu, Cu alloys, Cu compounds (Cu + non‐metal), and supported Cu‐based catalysts (Cu supported by carbon, metal oxides, or polymers). The detailed mechanisms for the selective CO2RR are presented, followed by recent relevant developments on the synthetic procedures for preparing Cu and Cu‐based nanoparticles. Herein, the potential link between the Cu surface and CO2RR performance is highlighted, especially in terms of the chemical states, but other significant factors such as defective sites and roughened morphology of catalysts are equally considered during the discussion of current studies of CO2RR with Cu‐based electrocatalysts to fully understand the origin of the significant enhancement toward C2 formation. This report concludes by providing suggestions for future designs of highly selective and stable Cu‐based electrocatalysts for CO2RR.

Homogeneous and heterogeneous molecular catalysts for electrochemical reduction of carbon dioxide

“…Many studies of copper (Cu) electrodes have characterized their ability to reduce CO 2 to multi-carbon products, 14,33,55,87,[102][103][104][105][106][107][108][109][110] whereas when exposed to molecular catalysts it is more common to see CO 2 selectively converted to CO, 57 formate, 111 and formic acid. 13,104 We have also investigated the ability of primary amines to selectively reduce CO 2 to CO using Cu electrodes (Fig.…”

Design of CuInS2 hollow nanostructures toward CO2 electroreduction

“…Among all solutions to reduce the CO 2 level in the atmosphere, electrochemical reduction using renewable electricity is a promising strategy for fulfilling this goal. The activation of CO 2 into the CO 2 − radical anion and CO intermediate species usually requires high potential, forming a serious bottleneck [5]. Many studies have reported that copper-based material is one of the most efficient catalysts for converting CO 2 , while bimetallic systems typically exhibited higher activity and selectivity for CO 2 reduction as compared with monometallic catalysts.…”

Potentialabhängige Morphologie von Kupferkatalysatoren während der Elektroreduktion von CO2, ermittelt durch In‐situ‐Rasterkraftmikroskopie

“…[5,8] However, to rationally design robust, active and selective CO2RR catalysts, nanoscale structure-property relationships derived under reaction conditions are urgently required. [9] Disentangling structural and catalytic properties proves to be intricate due to the dynamic nature of copper electrocatalysts with their structure, morphology, composition and oxidation state becoming altered during CO2RR. [10] Previous works showed the dynamic evolution of Cu nanoparticles [11] and electrode restructuring induced by electrochemical potentials [12] or surfaceadsorbed species.…”

“…Um die C 2+ ‐Selektivität zu verbessern, wurden Kupfer‐Katalysatoren mit niedrigkoordinierten Zentren und Oberflächendefekten, abgestimmten Oxidationszuständen und Metallzusammensetzungen oder modifizierten Größen und Formen hergestellt [5, 8] . Für eine systematische Entwicklung von robusten, aktiven und selektiven CO 2 RR‐Katalysatoren sind genaue Kenntnisse der nanoskaligen Struktur‐Eigenschafts‐Beziehungen unter Reaktionsbedingungen dringend notwendig [9] …”