Electroreduction of CO₂: Advances in the Continuous Production of Formic Acid and Formate

ACS Energy Letters, Journal Year: 2023, Volume and Issue: 8(4), P. 1992 - 2024

Published: March 30, 2023

The study of the electrochemical CO2 reduction to obtain formate (HCOO–) or formic acid (HCOOH) is receiving much attention as a promising technology. Since continuous–mode operation has become necessary for practical implementation reduction, recent years have seen rapid increase in number research approaches focusing on this aspect. This Focus Review provides unified discussion available studies continuous electroreduction HCOO–/HCOOH, considering different important features process design. Moreover, paper quantitatively assesses performance that involve reactors converting HCOOH/HCOO–, comparing relevant typically used figures merit, including energy consumption. Although some trade-offs already been achieved, simultaneous optimization all merit remains challenge. Finally, concluding remarks highlight detected trends and discuss aspects will be tackled by future field.

Language: Английский

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Breaking Local Charge Symmetry of Iron Single Atoms for Efficient Electrocatalytic Nitrate Reduction to Ammonia

Angewandte Chemie International Edition, Journal Year: 2023, Volume and Issue: 62(39)

Published: July 22, 2023

The electrochemical conversion of nitrate pollutants into value-added ammonia is a feasible way to achieve artificial nitrogen cycle. However, the development electrocatalytic nitrate-to-ammonia reduction reaction (NO3- RR) has been hampered by high overpotential and low Faradaic efficiency. Here we develop an iron single-atom catalyst coordinated with phosphorus on hollow carbon polyhedron (denoted as Fe-N/P-C) NO3- RR electrocatalyst. Owing tuning effect atoms breaking local charge symmetry single-Fe-atom catalyst, it facilitates adsorption ions enrichment some key intermediates during process. Fe-N/P-C exhibits 90.3 % efficiency yield rate 17980 μg h-1 mgcat-1 , greatly outperforming reported Fe-based catalysts. Furthermore, operando SR-FTIR spectroscopy measurements reveal pathway based observed under different applied potentials durations. Density functional theory calculations demonstrate that optimized free energy ascribed asymmetric atomic interface configuration, which achieves optimal electron density distribution. This work demonstrates critical role atomic-level precision modulation heteroatom doping for RR, providing effective strategy improving catalytic performance single atom catalysts in reactions.

Language: Английский

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Stabilizing Oxidation State of SnO₂ for Highly Selective CO₂ Electroreduction to Formate at Large Current Densities

ACS Catalysis, Journal Year: 2023, Volume and Issue: 13(5), P. 3101 - 3108

Published: Feb. 16, 2023

Even though electrocatalytic CO2 reduction reaction (CO2RR) to formate has made significant advances, achieving a high cell energy efficiency at industrial-level current densities is still bottleneck for the large-scale application of this technology. SnO2 promising electrocatalyst production but restricted by unstable oxidation state under potentials, causing catalyst reconstruction and inactivation. Herein, we present an atomic doping strategy (by Cu, Bi, or Pt) trigger emergence oxygen vacancy in lattice stabilize during CO2RR. As result, optimal Cu-incorporated can keep Faradic >80% about 50–60% wide range up 500 mA cm–2 commercial flow cell, surpassing most reported works. A set situ spectroscopy measurements controlled electrochemical tests suggest that vacancy, induced participation Cu/Bi/Pt single atoms, holds key stabilizing as well promoting adsorption formate-related *OCHO intermediate. qualitative relationship between concentration CO2-to-formate conversion constructed on series doped catalysts.

Language: Английский

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In‐Situ Constructuring of Copper‐Doped Bismuth Catalyst for Highly Efficient CO₂ Electrolysis to Formate in Ampere‐Level

Advanced Energy Materials, Journal Year: 2022, Volume and Issue: 13(1)

Published: Nov. 6, 2022

Abstract CO 2 electrochemical reduction (CO RR) can mitigate environmental issues while providing valuable products, yet challenging in activity, selectivity, and stability. Here, a CuS‐Bi S 3 heterojunction precursor is reported that situ reconstruct to Cu‐doped Bismuth (CDB) electrocatalyst during RR. The CDB exhibits an industrial‐compatible current density of −1.1 A cm −2 record‐high formate formation rate 21.0 mmol h −1 at −0.86 V versus the reversible hydrogen electrode toward RR formate, dramatically outperforming currently catalysts. Importantly, ultrawide potential region 1050 mV with high Faradaic efficiency over 90% superior long‐term stability for more than 100 −400 mA also be realized. Experimental theoretical studies reveal remarkable performance results from doping effect Cu which optimizes adsorption *OCHO boosts structural metallic bismuth catalyst. This study provides inspiration design element‐doping electrocatalysts enhance catalytic activity durability.

Language: Английский

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Asymmetric Coordination Induces Electron Localization at Ca Sites for Robust CO₂ Electroreduction to CO

Advanced Materials, Journal Year: 2023, Volume and Issue: 35(21)

Published: March 16, 2023

Main group single atom catalysts (SACs) are promising for CO2 electroreduction to CO by virtue of their ability in preventing the hydrogen evolution reaction and poisoning. Unfortunately, delocalized orbitals reduce activation *COOH. Herein, an O doping strategy localize electrons on p-orbitals through asymmetric coordination Ca SAC sites (Ca-N3 O) is developed, thus enhancing activation. Theoretical calculations indicate that Ca-N3 improves electron-localization around promotes *COOH formation. X-ray absorption fine spectroscopy shows obtained features: one three N coordinated atoms with as a reactive site. In situ attenuated total reflection infrared proves As result, catalyst exhibits state-of-the-art turnover frequency ≈15 000 per hour H-cell large current density -400 mA cm-2 Faradaic efficiency (FE) ≥ 90% flow cell. Moreover, retain FE above even 30% diluted concentration.

Language: Английский

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Enhancing Selective Electrochemical CO₂ Reduction by In Situ Constructing Tensile-Strained Cu Catalysts

ACS Catalysis, Journal Year: 2023, Volume and Issue: 13(7), P. 4711 - 4718

Published: March 23, 2023

Heteroatom-doped Cu-based catalysts have been found to show not only enhanced activity of electrochemical CO2 reduction reaction (CO2RR) but also the possibility tune selectivity CO2RR. However, complex and variable nature materials renders it difficult elucidate origin improved performance, which further hinders rational design catalysts. Here, we demonstrate that CO2RR can be tuned by manipulating lattice strain The combined operando ex situ spectroscopic characterizations reveal initial compressively strained Sn-doped CuO could converted tensile-strained Sn/Cu alloy under conditions. In attenuated total reflectance surface-enhanced infrared absorption spectroscopy (ATR-SEITAS) theoretical calculations favor CO formation due preponderant adsorption *CO much lower free energies *COOH, thus effectively suppressing dimerization process production HCOOH H2. This work provides a strategy performance strain.

Language: Английский

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Surface-Oxygen-Rich Bi@C Nanoparticles for High-Efficiency Electroreduction of CO₂ to Formate

Nano Letters, Journal Year: 2022, Volume and Issue: 22(22), P. 9107 - 9114

Published: Nov. 1, 2022

The electrochemical CO2 reduction reaction (CO2RR) is a promising strategy to alleviate excessive levels in the atmosphere and produce value-added feedstocks fuels. However, synthesis of high-efficiency robust electrocatalysts remains great challenge. This work reports green preparation surface-oxygen-rich carbon-nanorod-supported bismuth nanoparticles (SOR Bi@C NPs) for an efficient CO2RR toward formate. resultant SOR NPs catalyst displays Faradaic efficiency more than 91% formate generation over wide potential range 440 mV. Ex situ XPS XANES Raman spectroscopy demonstrate that Bi-O/Bi (110) structure pristine can remain stable during process. DFT calculations reveal facilitate formation *OCHO intermediate. provides approach development Bi-based catalysts offers unique insight into exploration advanced electrocatalysts.

Language: Английский

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Superscalar Phase Boundaries Derived Multiple Active Sites in SnO₂/Cu₆Sn₅/CuO for Tandem Electroreduction of CO₂ to Formic Acid

Advanced Energy Materials, Journal Year: 2023, Volume and Issue: 13(13)

Published: Feb. 12, 2023

Abstract The electrocatalytic CO 2 reduction reaction (CO RR) to fuels driven by electrocatalysts is a viable strategy for efficient utilization of emitted . RR involves multiple‐steps, including adsorption, activation, hydrogenation, etc. At present, copper‐tin alloy catalysts have shown the capability reduce formic acid or formate. However, their poor adsorption and activation capacities molecules, as well sluggish kinetics in *H supply restrict proton‐coupled electron transfer processes produce acid. In order solve above problems, ultra‐small SnO /Cu 6 Sn 5 /CuO nanocatalysts with superscalar phase boundaries are fabricated laser sputtering. introduction enhances , while CuO promotes H O decomposition provides abundant intermediates, resulting tandem catalytic sites on composite thus leading excellent activity high selectivity Faradic efficiency (FE HCOOH ) at electrode reaches 90.13% along current density 25.2 mA cm −2 −0.95 V versus reversible hydrogen electrode. role multiphase constructed oxides confirmed situ infrared spectroscopy kinetic isotope effects experiments, which consistent design concept.

Language: Английский

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Asymmetric Atomic Tin Catalysts with Tailored p‐Orbital Electron Structure for Ultra‐Efficient Oxygen Reduction

Advanced Energy Materials, Journal Year: 2024, Volume and Issue: 14(12)

Published: Jan. 28, 2024

Abstract Atomically dispersed transition metal–nitrogen–carbon (M–N–C) catalysts guide by the d‐band center theory have been extensively studied for oxygen reduction reaction (ORR) in various energy conversion and storage processes. However, asymmetric p‐block metal single‐atom (SACs) toward ORR rarely reported, origin of their catalytic activity is still unclear. Here, an N, O coordinated Sn SAC developed as efficient electrocatalyst. Remarkably, optimized (e.g., Sn–N/O–C) exhibit outstanding performance with a half‐wave potential 0.910 V alkaline media, outperforming most state‐of‐the‐art catalysts. More importantly, Sn–N/O–C possesses long‐term durability both acidic electrolytes. Besides, Zn–air batteries based on cathode also show higher density (254 mW cm ‐2 ) than that reported M–N–C counterparts. Theoretical calculations suggest atomic sites stronger binding interaction 2 better charge transfer ability compared symmetric SnN 4 sites, thereby facilitating process. This work provides nitrogen‐, oxygen‐coordinated engineering strategy rational design highly active durable carbon‐based beyond.

Language: Английский

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Efficient Capture and Electroreduction of Dilute CO₂ into Highly Pure and Concentrated Formic Acid Aqueous Solution

Journal of the American Chemical Society, Journal Year: 2024, Volume and Issue: 146(20), P. 14349 - 14356

Published: May 14, 2024

High-purity CO2 rather than dilute (15 vol %, CO2/N2/O2 = 15:80:5, v/v/v) similar to the flue gas is currently used as feedstock for electroreduction of CO2, and liquid products are usually mixed up with cathode electrolyte, resulting in high product separation costs. In this work, we showed that a microporous conductive Bi-based metal–organic framework (Bi-HHTP, HHTP 2,3,6,7,10,11-hexahydroxytriphenylene) can not only efficiently capture from under humidity but also catalyze adsorbed into formic acid current density 80 mA cm–2 Faradaic efficiency 90% at very low cell voltage 2.6 V. Importantly, performance atmosphere was close high-purity atmosphere. This first catalyst maintain exceptional eCO2RR presence both O2 N2. Moreover, by using feedstock, 1 working electrode coating Bi-HHTP continuously produce 200 mM aqueous solution relative purity 100% least 30 h membrane assembly (MEA) electrolyzer. The does contain electrolytes, such highly concentrated pure be directly an electrolyte fuel cells. Comprehensive studies revealed might ascribed ability micropores on lower Gibbs free energy formation key intermediate *OCHO open Bi sites.

Language: Английский

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