1
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Ma M, Seger B. Rational Design of Local Reaction Environment for Electrocatalytic Conversion of CO 2 into Multicarbon Products. Angew Chem Int Ed Engl 2024; 63:e202401185. [PMID: 38576259 DOI: 10.1002/anie.202401185] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2024] [Revised: 04/03/2024] [Accepted: 04/04/2024] [Indexed: 04/06/2024]
Abstract
The electrocatalytic conversion of CO2 into multi-carbon (C2+) products provides an attractive route for storing intermittent renewable electricity as fuels and feedstocks with high energy densities. Although substantial progress has been made in selective electrosynthesis of C2+ products via engineering the catalyst, rational design of the local reaction environment in the vicinity of catalyst surface also acts as an effective approach for further enhancing the performance. Here, we discuss recent advances and pertinent challenges in the modulation of local reaction environment, encompassing local pH, the choice of the species and concentrations of cations and anions as well as local reactant/intermediate concentrations, for achieving high C2+ selectivity. In addition, mechanistic understanding in the effects of the local reaction environment is also discussed. Particularly, the important progress extracted from in situ and operando spectroscopy techniques provides insights into how local reaction environment affects C-C coupling and key intermediates formation that lead to reaction pathways toward a desired C2+ product. The possible future direction in understanding and engineering the local reaction environment is also provided.
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Affiliation(s)
- Ming Ma
- School of Chemical Engineering and Technology, Xi'an Jiaotong University, Xi'an, 710049, People's Republic of China
| | - Brian Seger
- Surface Physics and Catalysis (Surfcat) Section, Department of Physics, Technical University of Denmark, 2800, Kgs. Lyngby, Denmark
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2
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Goyal A, Louisia S, Moerland P, Koper MTM. Cooperative Effect of Cations and Catalyst Structure in Tuning Alkaline Hydrogen Evolution on Pt Electrodes. J Am Chem Soc 2024; 146:7305-7312. [PMID: 38451209 PMCID: PMC10958517 DOI: 10.1021/jacs.3c11866] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2023] [Revised: 02/09/2024] [Accepted: 02/09/2024] [Indexed: 03/08/2024]
Abstract
The kinetics of hydrogen evolution reaction (HER) in alkaline media, a reaction central to alkaline water electrolyzers, is not accurately captured by traditional adsorption-based activity descriptors. As a result, the exact mechanism and the main driving force for the water reduction or HER rate remain hotly debated. Here, we perform extensive kinetic measurements on the pH- and cation-dependent HER rate on Pt single-crystal electrodes in alkaline conditions. We find that cations interacting with Pt step sites control the HER activity, while they interact only weakly with Pt(111) and Pt(100) terraces and, therefore, cations do not affect HER kinetics on terrace sites. This is reflected by divergent activity trends as a function of pH as well as cation concentration on stepped Pt surfaces vs Pt surfaces that do not feature steps, such as Pt(111). We show that HER activity can be optimized by rationally tuning these step-cation interactions via selective adatom deposition at the steps and by choosing an optimal electrolyte composition. Our work shows that the catalyst and the electrolyte must be tailored in conjunction to achieve the highest possible HER activity.
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Affiliation(s)
- Akansha Goyal
- Leiden Institute of Chemistry, Leiden University, P.O. Box 9502, 2300 RA Leiden, The Netherlands
| | - Sheena Louisia
- Leiden Institute of Chemistry, Leiden University, P.O. Box 9502, 2300 RA Leiden, The Netherlands
| | - Pricilla Moerland
- Leiden Institute of Chemistry, Leiden University, P.O. Box 9502, 2300 RA Leiden, The Netherlands
| | - Marc T. M. Koper
- Leiden Institute of Chemistry, Leiden University, P.O. Box 9502, 2300 RA Leiden, The Netherlands
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3
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Shen L, Goyal A, Chen X, Koper MTM. Cation Effects on Hydrogen Oxidation Reaction on Pt Single-Crystal Electrodes in Alkaline Media. J Phys Chem Lett 2024; 15:2911-2915. [PMID: 38451074 PMCID: PMC10945570 DOI: 10.1021/acs.jpclett.4c00292] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2024] [Revised: 02/28/2024] [Accepted: 03/01/2024] [Indexed: 03/08/2024]
Abstract
The exact mechanism behind the cation-assisted hydrogen oxidation reaction (HOR) on platinum electrodes in alkaline media remains disputed. We show that the cation effects at platinum display a remarkable structure sensitivity: not only the H adsorption but also the HOR activity on (111) terrace sites are independent of the nature of cation and cation concentration. On (110) step sites, at low cation concentration and mildly alkaline media, cations promote the HOR, whereas at more alkaline pH and consequently higher near-surface cation concentrations, the HOR is inhibition by the cations. Moreover, the role of the cation on terrace-OHad is different from that on step-OHad, as can also be observed from the inhibition of the HOR current by terrace-OHad at higher potentials. These results suggest that near the onset potential, HOR mainly takes place on steps, but under diffusion-limited conditions at higher overpotential, HOR mainly takes place on terraces.
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Affiliation(s)
- Linfan Shen
- Leiden
Institute of Chemistry, Leiden University, PO Box 9502, 2300 RA Leiden, The Netherlands
| | - Akansha Goyal
- Leiden
Institute of Chemistry, Leiden University, PO Box 9502, 2300 RA Leiden, The Netherlands
| | - Xiaoting Chen
- Leiden
Institute of Chemistry, Leiden University, PO Box 9502, 2300 RA Leiden, The Netherlands
- School
of Materials Science and Engineering, Beijing
Institute of Technology, Beijing 100081, P. R. China
| | - Marc T. M. Koper
- Leiden
Institute of Chemistry, Leiden University, PO Box 9502, 2300 RA Leiden, The Netherlands
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4
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Wu T, Bu H, Tao S, Ma M. Determination of local pH in CO 2 electroreduction. NANOSCALE 2024; 16:3926-3935. [PMID: 38323700 DOI: 10.1039/d3nr06357g] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/08/2024]
Abstract
The electrocatalytic conversion of CO2 and H2O into fuels and valuable chemicals has gained significant interest as a prospective method for the storage of renewable energy and the utilization of captured CO2. In the process of electroreduction of CO2, pH near the surface of the electrocatalysts plays an important role in the catalytic selectivity and activity. However, to elucidate the local pH effect on the fundamental reaction mechanism and modify the catalytic CO2 reduction performance, the localized pH determination method is highly desirable. In this minireview, we present the recent advances in the strategies of the local pH probe for CO2 electrolysis in both H-type cell reactors and GDE-type flow electrolyzers, followed with a better understanding of the local reaction environment in CO2 reduction. Additionally, pertinent advantages and drawbacks of the different localized pH probe techniques are discussed, and perspectives on future research efforts are also provided in this minireview.
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Affiliation(s)
- Tiantian Wu
- School of Chemical Engineering and Technology, Xi'an Jiaotong University, Xi'an 710049, People's Republic of China.
- School of Chemistry, Xi'an Jiaotong University, Xi'an 710049, People's Republic of China
| | - Hangyu Bu
- School of Chemical Engineering and Technology, Xi'an Jiaotong University, Xi'an 710049, People's Republic of China.
| | - Shuaikang Tao
- School of Chemical Engineering and Technology, Xi'an Jiaotong University, Xi'an 710049, People's Republic of China.
| | - Ming Ma
- School of Chemical Engineering and Technology, Xi'an Jiaotong University, Xi'an 710049, People's Republic of China.
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5
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Liu BY, Zhen EF, Zhang LL, Cai J, Huang J, Chen YX. The pH-Induced Increase of the Rate Constant for HER at Au(111) in Acid Revealed by Combining Experiments and Kinetic Simulation. Anal Chem 2024; 96:67-75. [PMID: 38153001 DOI: 10.1021/acs.analchem.3c02818] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2023]
Abstract
Origins of pH effects on the kinetics of electrocatalytic reactions involving the transfer of both protons and electrons, including the hydrogen evolution reaction (HER) considered in this study, are heatedly debated. By taking the HER at Au(111) in acid solutions of different pHs and ionic concentrations as the model systems, herein, we report how to derive the intrinsic kinetic parameters of such reactions and their pH dependence through the measurement of j-E curves and the corresponding kinetic simulation based on the Frumkin-Butler-Volmer theory and the modified Poisson-Nernst-Planck equation. Our study reveals the following: (i) the same set of kinetic parameters, such as the standard activation Gibbs free energy, charge transfer coefficient, and Gibbs adsorption energy for Had at Au(111), can simulate well all the j-E curves measured in solutions with different pH and temperatures; (ii) on the reversible hydrogen electrode scale, the intrinsic rate constant increases with the increase of pH, which is in contrast with the decrease of the HER current with the increase of pH; and (iii) the ratio of the rate constants for HER at Au(111) in x M HClO4 + (0.1 - x) M NaClO4 (pH ≤ 3) deduced before properly correcting the electric double layer (EDL) effects to the ones estimated with EDL correction is in the range of ca. 10 to 40, and even in a solution of x M HClO4 + (1 - x) M NaClO4 (pH ≤ 2) there is a difference of ca. 5× in the rate constants without and with EDL correction. The importance of proper correction of the EDL effects as well as several other important factors on unveiling the intrinsic pH-dependent reaction kinetics are discussed to help converge our analysis of pH effects in electrocatalysis.
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Affiliation(s)
- Bing-Yu Liu
- Hefei National Research Center for Physical Sciences at Microscale, Department of Chemical Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Er-Fei Zhen
- Hefei National Research Center for Physical Sciences at Microscale, Department of Chemical Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Lu-Lu Zhang
- Hefei National Research Center for Physical Sciences at Microscale, Department of Chemical Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Jun Cai
- Hefei National Research Center for Physical Sciences at Microscale, Department of Chemical Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Jun Huang
- Institute of Energy and Climate Research, IEK-13: Theory and Computation of Energy Materials, Forschungszentrum Jülich GmbH, 52425 Jülich, Germany
- Theorie Elektrokatalytischer Grenzflächen, Fakultät für Georessourcen und Materialtechnik, RWTH Aachen University, 52062 Aachen, Germany
| | - Yan-Xia Chen
- Hefei National Research Center for Physical Sciences at Microscale, Department of Chemical Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
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6
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Dawlaty JM, Perkin S, Salanne M, Willard AP. The chemical physics of electrode-electrolyte interfaces. J Chem Phys 2023; 159:150401. [PMID: 37846953 DOI: 10.1063/5.0177099] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2023] [Accepted: 09/25/2023] [Indexed: 10/18/2023] Open
Affiliation(s)
- Jahan M Dawlaty
- Department of Chemistry, University of Southern California, Los Angeles, California 90089, USA
| | - Susan Perkin
- Department of Chemistry, Physical and Theoretical Chemistry Laboratory, University of Oxford, Oxford OX1 3QZ, United Kingdom
| | - Mathieu Salanne
- Sorbonne Université, CNRS, Physicochimie des Électrolytes et Nanosystèmes Interfaciaux, F-75005 Paris, France
| | - Adam P Willard
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 01239, USA
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7
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Sargeant E, Rodriguez P. Determination of Kinematic Viscosity of Mg(ClO 4) 2 and KOH Brines Saturated with CO 2 at Sub-Zero Temperatures. Molecules 2023; 28:5641. [PMID: 37570611 PMCID: PMC10419985 DOI: 10.3390/molecules28155641] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2023] [Revised: 07/20/2023] [Accepted: 07/21/2023] [Indexed: 08/13/2023] Open
Abstract
The current race for space exploration has hastened the development of electrochemical technologies for the in-situ utilisation of planetary resources for the synthesis of vital chemicals such as O2 and fuels. Understanding the physicochemical properties, such as the density and kinematic viscosity, of aqueous solutions is essential for the design of electrochemical devices for the electrolysis of water and CO2, particularly at low temperatures. The density and kinematic viscosity of highly concentrated Mg(ClO4)2 and KOH solutions have been determined, both at low temperatures and in the presence of CO2 gas. It was found that, for all of the solutions, independent of the concentration or nature of the electrolyte, as the temperature was decreased to 255 K, the density and the viscosity of the solutions increased. Upon saturation with CO2, no significant change to the density and viscosity of Mg(ClO4)2, at all of the temperatures measured, was observed. Conversely, the CO2 saturated solutions of KOH showed significant changes in density and viscosity at all temperatures, likely due to the formation of carbonates. The effects of these changes on the diffusion coefficient for dissolved CO2 is also discussed.
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Affiliation(s)
| | - Paramaconi Rodriguez
- School of Chemistry, University of Birmingham, Birmingham B15 2TT, UK
- Centre for Cooperative Research on Alternative Energies (CICenergiGUNE), Basque Research and Technology Alliance (BRTA), Alava Technology Park, 01510 Vitoria-Gasteiz, Spain
- Ikerbasque, Basque Foundation for Science, 48013 Bilbao, Spain
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8
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Chavez M, Biset-Peiró M, Murcia-López S, Morante JR. Cu 2O-Cu@Titanium Surface with Synergistic Performance for Nitrate-to-Ammonia Electrochemical Reduction. ACS SUSTAINABLE CHEMISTRY & ENGINEERING 2023; 11:3633-3643. [PMID: 36911876 PMCID: PMC9993578 DOI: 10.1021/acssuschemeng.2c05885] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/30/2022] [Revised: 01/26/2023] [Indexed: 06/18/2023]
Abstract
Transition metals, such as titanium (Ti) and copper (Cu) along with their respective metal oxides (TiO2, Cu2O, and CuO), have been widely studied as electrocatalysts for nitrate electrochemical reduction with important outcomes in the fields of denitrification and ammonia generation. Based on this, this work conducted an evaluation of a composite electrode that integrates materials with different intrinsic activities (i.e., Cu and Cu2O for higher activity for nitrate conversion; Ti for higher faradaic efficiency to ammonia) looking for potential synergistic effects in the direction of ammonia generation. The specific performance of single-metal and composite electrodes has shown a strong dependence on pH and nitrate concentration conditions. Faradaic efficiency to ammonia of 92% and productivities of 0.28 mmolNH3 ·cm-2·h-1 at 0.5 V vs reversible hydrogen electrode (RHE) values are achieved, demonstrating the implicit potential of this approach in comparison to direct N2RR with values in the order of μmolNH3 ·h-1·cm-2. Finally, the electrochemical rate constants (k) for Ti, Cu, and Cu2O-Cu/Ti disk electrodes were determined by the Koutecky-Levich analysis with a rotating disk electrode (RDE) in 3.02 × 10-6, 3.88 × 10-4, and 4.77 × 10-4 cm·s-1 demonstrating an apparent synergistic effect for selective NiRR to ammonia with a Cu2O-Cu/Ti electrode.
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Affiliation(s)
- Marcelo
Eduardo Chavez
- Catalonia
Institute for Energy Research (IREC), Jardins de les Dones de Negre 1, Sant Adrià de Besós 08930, Spain
| | - Martí Biset-Peiró
- Catalonia
Institute for Energy Research (IREC), Jardins de les Dones de Negre 1, Sant Adrià de Besós 08930, Spain
| | - Sebastián Murcia-López
- Catalonia
Institute for Energy Research (IREC), Jardins de les Dones de Negre 1, Sant Adrià de Besós 08930, Spain
| | - Joan Ramon Morante
- Catalonia
Institute for Energy Research (IREC), Jardins de les Dones de Negre 1, Sant Adrià de Besós 08930, Spain
- Facultat
de Física, Universitat de Barcelona, C. Martí i Franqués,
1, Barcelona 08028, Spain
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9
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Liu X, Monteiro MCO, Koper MTM. Interfacial pH measurements during CO 2 reduction on gold using a rotating ring-disk electrode. Phys Chem Chem Phys 2023; 25:2897-2906. [PMID: 36633182 DOI: 10.1039/d2cp05515e] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Insights into how to control the activity and selectivity of the electrochemical CO2 reduction reaction are still limited because of insufficient knowledge of the reaction mechanism and kinetics, which is partially due to the lack of information on the interfacial pH, an important parameter for proton-coupled reactions like CO2 reduction. Here, we used a reliable and sensitive pH sensor combined with the rotating ring-disk electrode technique, in which a functionalized Au ring electrode works as a real-time detector of the OH- generated during the CO2 reduction reaction at a gold disk electrode. Variations of the interfacial pH due to both electrochemical and homogeneous reactions are mapped and the correlation of the interfacial pH with these reactions is inferred. The interfacial pH near the disk electrode increases from 7 to 12 with increasing current density, with a sharp increase at around -0.5 V vs. RHE, which indicates a change of the dominant buffering species. Through scan rate-dependent voltammetry and chronopotentiometry experiments, the homogenous reactions are shown to reach equilibrium within the time scale of the pH measurements, so that the interfacial concentrations of different carbonaceous species can be calculated using equilibrium constants. Furthermore, pH measurements were also performed under different conditions to disentangle the relationship between the interfacial pH and other electrolyte effects. The buffer effect of alkali metal cations is confirmed, showing that weakly hydrated cations lead to less pronounced pH gradients. Finally, we probe to which extent increasing mass transport and the electrolyte buffer capacity can aid in suppressing the increase of the interfacial pH, showing that the buffer capacity is the dominant factor in suppressing interfacial pH variations.
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Affiliation(s)
- Xuan Liu
- Leiden Institute of Chemistry, Leiden University, 2300 RA Leiden, The Netherlands.
| | - Mariana C O Monteiro
- Leiden Institute of Chemistry, Leiden University, 2300 RA Leiden, The Netherlands.
| | - Marc T M Koper
- Leiden Institute of Chemistry, Leiden University, 2300 RA Leiden, The Netherlands.
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10
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Qin X, Vegge T, Hansen HA. Cation-Coordinated Inner-Sphere CO 2 Electroreduction at Au-Water Interfaces. J Am Chem Soc 2023; 145:1897-1905. [PMID: 36630567 DOI: 10.1021/jacs.2c11643] [Citation(s) in RCA: 15] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Electrochemical CO2 reduction reaction (CO2RR) is a promising technology for the clean energy economy. Numerous efforts have been devoted to enhancing the mechanistic understanding of CO2RR from both experimental and theoretical studies. Electrolyte ions are critical for the CO2RR; however, the role of alkali metal cations is highly controversial, and a complete free energy diagram of CO2RR at Au-water interfaces is still missing. Here, we provide a systematic mechanism study toward CO2RR via ab initio molecular dynamics simulations integrated with the slow-growth sampling (SG-AIMD) method. By using the SG-AIMD approach, we demonstrate that CO2RR is facile at the inner-sphere interface in the presence of K cations, which promote the CO2 activation with the free energy barrier of only 0.66 eV. Furthermore, the competitive hydrogen evolution reaction (HER) is inhibited by the interfacial cations with the induced kinetic blockage effect, where the rate-limiting Volmer step shows a much higher energy barrier (1.27 eV). Eventually, a comprehensive free energy diagram including both kinetics and thermodynamics of the CO2RR to CO and the HER at the electrochemical interface is derived, which illustrates the critical role of cations on the overall performance of CO2 electroreduction by facilitating CO2 adsorption while suppressing the hydrogen evolution at the same time.
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Affiliation(s)
- Xueping Qin
- Department of Energy Conversion and Storage, Technical University of Denmark, Kgs. Lyngby2800, Denmark
| | - Tejs Vegge
- Department of Energy Conversion and Storage, Technical University of Denmark, Kgs. Lyngby2800, Denmark
| | - Heine Anton Hansen
- Department of Energy Conversion and Storage, Technical University of Denmark, Kgs. Lyngby2800, Denmark
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11
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The role of alkali metal cations and platinum-surface hydroxyl in the alkaline hydrogen evolution reaction. Nat Catal 2022. [DOI: 10.1038/s41929-022-00851-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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12
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Marcandalli G, Monteiro MCO, Goyal A, Koper MTM. Electrolyte Effects on CO 2 Electrochemical Reduction to CO. Acc Chem Res 2022; 55:1900-1911. [PMID: 35772054 PMCID: PMC9301915 DOI: 10.1021/acs.accounts.2c00080] [Citation(s) in RCA: 58] [Impact Index Per Article: 29.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
![]()
The electrochemical reduction of CO2 (CO2RR) constitutes
an alternative to fossil fuel-based technologies for the production
of fuels and commodity chemicals. Yet the application of CO2RR electrolyzers
is hampered by low energy and Faradaic efficiencies. Concomitant electrochemical
reactions, like hydrogen evolution (HER), lower the selectivity, while
the conversion of CO2 into (bi)carbonate through solution
acid–base reactions induces an additional concentration overpotential.
During CO2RR in aqueous media, the local pH becomes more alkaline
than the bulk causing an additional consumption of CO2 by
the homogeneous reactions. The latter effect, in combination with
the low solubility of CO2 in aqueous electrolytes (33 mM),
leads to a significant depletion in CO2 concentration at
the electrode surface. The nature of the electrolyte, in terms
of pH and cation identity,
has recently emerged as an important factor to tune both the energy
and Faradaic efficiency. In this Account, we summarize the recent
advances in understanding electrolyte effects on CO2RR to CO in aqueous
solutions, which is the first, and crucial, step to further reduced
products. To compare literature findings in a meaningful way, we focus
on results reported under well-defined mass transport conditions and
using online analytical techniques. The discussion covers the molecular-level
understanding of the effects of the proton donor, in terms of the
suppression of the CO2 gradient vs enhancement of HER at
a given mass transport rate and of the cation, which is crucial in
enabling both CO2RR and HER. These mechanistic insights are then translated
into possible implications for industrially relevant cell geometries
and current densities.
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Affiliation(s)
- Giulia Marcandalli
- Leiden Institute of Chemistry, Leiden University, P.O. Box 9502, 2300 RA Leiden, The Netherlands
| | - Mariana C O Monteiro
- Leiden Institute of Chemistry, Leiden University, P.O. Box 9502, 2300 RA Leiden, The Netherlands
| | - Akansha Goyal
- Leiden Institute of Chemistry, Leiden University, P.O. Box 9502, 2300 RA Leiden, The Netherlands
| | - Marc T M Koper
- Leiden Institute of Chemistry, Leiden University, P.O. Box 9502, 2300 RA Leiden, The Netherlands
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13
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Kastlunger G, Wang L, Govindarajan N, Heenen HH, Ringe S, Jaramillo T, Hahn C, Chan K. Using pH Dependence to Understand Mechanisms in Electrochemical CO Reduction. ACS Catal 2022. [DOI: 10.1021/acscatal.1c05520] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Affiliation(s)
- Georg Kastlunger
- Catalysis Theory Center, Department of Physics, Technical University of Denmark (DTU), 2800 Kgs. Lyngby, Denmark
| | - Lei Wang
- SUNCAT Center for Interface Science and Catalysis, Department of Chemical Engineering, Stanford University, Stanford, California 94305, United States
- Department of Chemical and Biomolecular Engineering, National University of Singapore, Singapore 117585, Singapore
| | - Nitish Govindarajan
- Catalysis Theory Center, Department of Physics, Technical University of Denmark (DTU), 2800 Kgs. Lyngby, Denmark
| | - Hendrik H. Heenen
- Catalysis Theory Center, Department of Physics, Technical University of Denmark (DTU), 2800 Kgs. Lyngby, Denmark
| | - Stefan Ringe
- Department of Energy Science and Engineering, Daegu Gyeongbuk Institute of Science and Technology, Daegu 42988, Republic of Korea
- Energy Science and Engineering Research Center, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Daegu 42988, Republic of Korea
- Department of Chemistry, Korea University, Seoul 02841, Republic of Korea
- Center for Molecular Spectroscopy and Dynamics, Institute for Basic Science, Seoul 02841, Republic of Korea
| | - Thomas Jaramillo
- SUNCAT Center for Interface Science and Catalysis, Department of Chemical Engineering, Stanford University, Stanford, California 94305, United States
| | - Christopher Hahn
- SUNCAT Center for Interface Science and Catalysis, SLAC National Accelerator Laboratory, Menlo Park, California 94025, United States
- Materials Science Division, Lawrence Livermore National Laboratory, Livermore, California 94550, United States
| | - Karen Chan
- Catalysis Theory Center, Department of Physics, Technical University of Denmark (DTU), 2800 Kgs. Lyngby, Denmark
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14
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Xu A, Govindarajan N, Kastlunger G, Vijay S, Chan K. Theories for Electrolyte Effects in CO 2 Electroreduction. Acc Chem Res 2022; 55:495-503. [PMID: 35107967 DOI: 10.1021/acs.accounts.1c00679] [Citation(s) in RCA: 21] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Electrochemical CO2 reduction (eCO2R) enables the conversion of waste CO2 to high-value fuels and commodity chemicals powered by renewable electricity, thereby offering a viable strategy for reaching the goal of net-zero carbon emissions. Research in the past few decades has focused both on the optimization of the catalyst (electrode) and the electrolyte environment. Surface-area normalized current densities show that the latter can affect the CO2 reduction activity by up to a few orders of magnitude.In this Account, we review theories of the mechanisms behind the effects of the electrolyte (cations, anions, and the electrolyte pH) on eCO2R. As summarized in the conspectus graphic, the electrolyte influences eCO2R activity via a field (ε) effect on dipolar (μ) reaction intermediates, changing the proton donor for the multi-step proton-electron transfer reaction, specifically adsorbed anions on the catalyst surface to block active sites, and tuning the local environment by homogeneous reactions. To be specific, alkali metal cations (M+) can stabilize reaction intermediates via electrostatic interactions with dipolar intermediates or buffer the interfacial pH via hydrolysis reactions, thereby promoting the eCO2R activity with the following trend in hydrated size (corresponding to the local field strength ε)/hydrolysis ability: Cs+ > K+ > Na+ > Li+. The effect of the electrolyte pH can give a change in eCO2R activity of up to several orders of magnitude, arising from linearly shifting the absolute interfacial field via the relationship USHE = URHE - (2.3kBT)pH, homogeneous reactions between OH- and desorbed intermediates, or changing the proton donor from hydronium to water along with increasing pH. Anions have been suggested to affect the eCO2R reaction process by solution-phase reactions (e.g., buffer reactions to tune local pH), acting as proton donors or as a surface poison.So far, the existing models of electrolyte effects have been used to rationalize various experimentally observed trends, having yet to demonstrate general predictive capabilities. The major challenges in our understanding of the electrolyte effect in eCO2R are (i) the long time scale associated with a dynamic ab initio picture of the catalyst|electrolyte interface and (ii) the overall activity determined by the length-scale interplay of intrinsic microkinetics, homogeneous reactions, and mass transport limitations. New developments in ab initio dynamic models and coupling the effects of mass transport can provide a more accurate view of the structure and intrinsic functions of the electrode-electrolyte interface and the corresponding reaction energetics toward comprehensive and predictive models for electrolyte design.
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Affiliation(s)
- Aoni Xu
- Catalysis Theory Center, Department of Physics, Technical University of Denmark, 2800 Kgs. Lyngby, Denmark
| | - Nitish Govindarajan
- Catalysis Theory Center, Department of Physics, Technical University of Denmark, 2800 Kgs. Lyngby, Denmark
| | - Georg Kastlunger
- Catalysis Theory Center, Department of Physics, Technical University of Denmark, 2800 Kgs. Lyngby, Denmark
| | - Sudarshan Vijay
- Catalysis Theory Center, Department of Physics, Technical University of Denmark, 2800 Kgs. Lyngby, Denmark
| | - Karen Chan
- Catalysis Theory Center, Department of Physics, Technical University of Denmark, 2800 Kgs. Lyngby, Denmark
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Marcandalli G, Boterman K, Koper MT. Understanding hydrogen evolution reaction in bicarbonate buffer. J Catal 2022. [DOI: 10.1016/j.jcat.2021.12.012] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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Monteiro MCO, Goyal A, Moerland P, Koper MTM. Understanding Cation Trends for Hydrogen Evolution on Platinum and Gold Electrodes in Alkaline Media. ACS Catal 2021; 11:14328-14335. [PMID: 34888121 PMCID: PMC8650008 DOI: 10.1021/acscatal.1c04268] [Citation(s) in RCA: 43] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2021] [Revised: 11/02/2021] [Indexed: 12/03/2022]
Abstract
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In this work, we
study how the cation identity and concentration
alter the kinetics of the hydrogen evolution reaction (HER) on platinum
and gold electrodes. A previous work suggested an inverted activity
trend as a function of alkali metal cation when comparing the performance
of platinum and gold catalysts in alkaline media. We show that weakly
hydrated cations (K+) favor HER on gold only at low overpotentials
(or lower alkalinity), whereas in more alkaline pH (or high overpotentials),
a higher activity is observed using electrolytes containing strongly
hydrated cations (Li+). We find a similar trend for platinum;
however, the inhibition of HER by weakly hydrated cations on platinum
is observed already at lower alkalinity and lower cation concentrations,
suggesting that platinum interacts more strongly with metal cations
than gold. We propose that weakly hydrated cations stabilize the transition
state of the water dissociation step more favorably due to their higher
near-surface concentration in comparison to a strongly hydrated cation
such as Li+. However, at high pH and consequently higher
near-surface cation concentrations, the accumulation of these species
at the outer Helmholtz plane inhibits HER. This is especially pronounced
on platinum, where a change in the rate-determining step is observed
at pH 13 when using a Li+- or K+-containing
electrolyte.
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Affiliation(s)
- Mariana C. O. Monteiro
- Leiden Institute of Chemistry, Leiden University, P.O. Box 9502, 2300 RA Leiden, The Netherlands
| | - Akansha Goyal
- Leiden Institute of Chemistry, Leiden University, P.O. Box 9502, 2300 RA Leiden, The Netherlands
| | - Pricilla Moerland
- Leiden Institute of Chemistry, Leiden University, P.O. Box 9502, 2300 RA Leiden, The Netherlands
| | - Marc T. M. Koper
- Leiden Institute of Chemistry, Leiden University, P.O. Box 9502, 2300 RA Leiden, The Netherlands
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