Dynamic Evolution of Active Sites in Electrocatalytic CO₂ Reduction Reaction: Fundamental Understanding and Recent Progress

Abstract

Advancing the development of electrocatalytic CO2 reduction reaction (CO2RR) to address the environmental issues caused by excessive consumption of fossil fuels requires rational design of remarkable electrocatalysts, where the identification of active sites and further understanding of structure–performance relationship are the bases. However, the notable dynamic evolution often appears on the catalysts, with typical examples of Cu‐based catalysts, under operating conditions, causing great difficulty in identifying the real active sites and further understanding the correlations between structure and catalytic property. In this context, understanding the dynamic evolution process of catalytically active sites during CO2RR is of particular importance, which inspires to organize the present review. Herein, the fundamental principles of dynamic evolution in CO2RR including thermodynamics and kinetics aspects, followed by the introduction of operando techniques employed to probe the evolution under operating conditions are first highlighted. The dynamic evolution behaviors, involving atomic rearrangement and change in chemical state, on typical catalysts are further discussed, with emphasis on the correlations between evolution behaviors and catalytic properties (activity, selectivity, and stability). The emerging CO2 pulsed electrolysis technique that behaves promise to manipulate the dynamic evolution and future opportunities are finally discussed.

Intermetallic Nanocrystals: Seed‐Mediated Synthesis and Applications in Electrocatalytic Reduction Reactions

“…Excessive consumption of fossil fuels result in excess CO 2 emissions and brings numerous environmental problems including air pollution and global warming. [5][6][7][8][9] The ECO 2 RR not only provides a potential solution for reducing greenhouse gas in the atmosphere but also is able to simultaneously produce valuable carbonaceous fuels in the ambient atmosphere. [5][6][7][8][9] However, ECO 2 RR is a complicated reaction involved with a multistep electron-proton transfer process, resulting in various products such as formic acid, hydrogen, CO, and hydrocarbons.…”

“…[5][6][7][8][9] The ECO 2 RR not only provides a potential solution for reducing greenhouse gas in the atmosphere but also is able to simultaneously produce valuable carbonaceous fuels in the ambient atmosphere. [5][6][7][8][9] However, ECO 2 RR is a complicated reaction involved with a multistep electron-proton transfer process, resulting in various products such as formic acid, hydrogen, CO, and hydrocarbons. [5][6][7][8][9] Furthermore, driving ECO 2 RR requires a high overpotential of about À 1.0 V arising from its intrinsic thermodynamically uphill reaction, leading to the competition with a variety of reactions like hydrogen evolution reaction (HER).…”

“…[5][6][7][8][9] However, ECO 2 RR is a complicated reaction involved with a multistep electron-proton transfer process, resulting in various products such as formic acid, hydrogen, CO, and hydrocarbons. [5][6][7][8][9] Furthermore, driving ECO 2 RR requires a high overpotential of about À 1.0 V arising from its intrinsic thermodynamically uphill reaction, leading to the competition with a variety of reactions like hydrogen evolution reaction (HER). [5][6][7][8][9] This will bring low Faradaic efficiency (FE), which is used as a common parameter to represent the product selectivity for catalysts in ECO 2 RR.…”

“…Electrocatalytic reduction reactions play an important role in many environmental and energy fields, for example, electrocatalytic oxygen reduction reaction (ORR) determines the performance of proton exchange membrane fuel cells (PEMFCs); [1][2][3][4] electrocatalytic CO 2 reduction reaction (ECO 2 RR) converts greenhouse gases into fuel, which is an effective means to mitigate environmental problems. [5][6][7][8][9] However, electrocatalytic reduction reactions including ORR and ECO 2 RR have been proven to be extremely challenging in practice because significant energy is required to break the strong OÀ O bonds (ORR), and C=O bonds (ECO 2 RR). [2,9] Therefore, the development of highly active and stable nanocatalysts is essential for electrocatalytic reduction reactions.…”

Recent progress of Bi-based electrocatalysts for electrocatalytic CO2 reduction

“…electrolytes, electrocatalysts, configurations of electrolytic cells, and reduction potentials). [19][20][21] Additionally, CO 2 as an electrochemical precursor can generate various high-value products and chemicals, such as carbon monoxide (CO), 22,23 methane (CH 4 ), 25,26 formic acid (HCOOH) or formate (HCOO − ), 27,28 methanol (CH 3 OH), 29,30 ethylene (C 2 H 4 ), 31,32 ethanol (CH 3 CH 2 OH), 34,35 and n-propanol (n-C 3 H 7 OH). 37,38 Among these carbon-containing products, HCOOH/HCOO − exhibits a high net present value by techno-economic assessments 12,43 and is useful and widely needed in the areas of producing chemicals and pharmaceuticals, supplying protons in proton-exchange membrane fuel cells, and functioning as an important hydrogen carrier.…”