Selective Nitrogen Reduction Reaction on Single-Atom Centers of Molybdenum-Based MXenes by Pulsing the Electrochemical Potential DOI
Divya Singh, Samad Razzaq,

Shohreh Faridi

et al.

Published: Jan. 1, 2025

Electrocatalytic reduction of dinitrogen is a promising route for sustainable production ammonia, although the selectivity challenge competing nitrogen (NRR) and hydrogen evolution reactions in aqueous electrolytes has not yet been solved. Single-atom catalysts (SACs) offer hope bridging this gap because they exhibit unique electronic structure reactivity catalytic transformations compared to conventional bulk materials. In addition, potential pulse experiments have shown that promote formation kinetically unfavorable products by efficiently modulating electrolyte at solid-liquid interface. So far, combination SACs NRR mutually exclusive, since are likely be degraded during anodic due metal dissolution. Using density functional theory calculations grand canonical framework, we demonstrate present communication molybdenum-based MXenes able overcome limitation: traditional SACs, form single-atom centers pulse, their SAC-like allows directed ammonia instead gaseous cathodic pulse. Our study paves way development high-performance materials with in-situ formed sites enable advances selective under applied bias.

Language: Английский

Importance of the Walden Inversion for the Activity Volcano Plot of Oxygen Evolution DOI Creative Commons
Kai S. Exner

Advanced Science, Journal Year: 2023, Volume and Issue: 10(36)

Published: Oct. 30, 2023

Abstract Since the birth of computational hydrogen electrode approach, it is considered that activity trends electrocatalysts in a homologous series can be quantified by construction volcano plots. This method aims to steer materials discovery identification catalysts with an improved reaction kinetics, though evaluated means thermodynamic descriptors. The conventional approach for plot oxygen evolution (OER) relies on assumption mononuclear mechanism, comprising * OH, O, and OOH intermediates. In present manuscript, two new mechanistic pathways, idea Walden inversion bond‐breaking bond‐making occurs simultaneously, are factored into potential‐dependent OER plot. Surprisingly, turns out plays important role since governed pathways steps rather than traditionally assumed mechanisms under typical conditions.

Language: Английский

Citations

17
MXenes as Electrocatalysts for the CO2 Reduction Reaction: Recent Advances and Future Challenges DOI Creative Commons
Ling Meng, Ebrahim Tayyebi, Kai S. Exner

et al.

ChemElectroChem, Journal Year: 2024, Volume and Issue: 11(5)

Published: Jan. 12, 2024

Abstract Electrochemical carbon dioxide reduction (CO 2 RR) is gaining momentum as an effective process to capture and convert CO into valuable chemicals fuels, well contribute reducing greenhouse gas emissions. Two‐dimensional transition metal carbides and/or nitrides (MXenes) are increasingly attracting attention RR electrocatalysts due their enhanced chemical activity selectivity, overcoming limitations of traditional electrocatalysts, likely breaking the scaling relations reaction intermediates toward desired product. The present concept reviews state‐of‐the‐art in computational description on MXenes, going from activation pristine models different surface terminations, discuss possible ways tune catalytic including doping, defects, supported single atoms, solvent effects, electric field while putting spotlight prospects by kinetic aspects.

Language: Английский

Citations

8
Is the ∗O vs. ∗OH scaling relation intercept more relevant than the ∗OOH vs. ∗OH intercept to capture trends in the oxygen evolution reaction? DOI Creative Commons
Maksim Sokolov, Kai S. Exner

Chem Catalysis, Journal Year: 2024, Volume and Issue: 4(7), P. 101039 - 101039

Published: July 1, 2024

The transition from fossil fuels to renewable energy sources is inevitable, and electrocatalytic water splitting produce hydrogen one of the core processes that must be further optimized. Regrettably, anodic oxygen evolution reaction (OER) severely limits its efficiency. Theory explains humble intrinsic activity OER catalysts by scaling relations between intermediates. While relation ∗OOH ∗OH intermediates well established, only slope ∗O vs.∗OH has an estimated numerical value, whereas intercept this frequently assumed zero. Herein, we demonstrate how deviations assumption cause changes in shape volcano plot prevalent mechanisms at apex plot. Our derived plots may enable progress design shifting focus on vs. relation.

Language: Английский

Citations

7
Computationally screening non-precious single atom catalysts for oxygen reduction in alkaline media DOI Creative Commons
Tahereh Jangjooye Shaldehi, Ling Meng, Soosan Rowshanzamir

et al.

Catalysis Today, Journal Year: 2024, Volume and Issue: 431, P. 114560 - 114560

Published: Feb. 3, 2024

The performance of single-atom catalysts (SACs) containing Sc, Ti, V, Mn, Fe, Ni, Cu, and Pt on N-doped carbon (NC) as possible cathodes in advanced chlor-alkali electrolysis has been investigated by means density functional theory (DFT) with the aim finding candidates to improve sluggish kinetics oxygen reduction reaction (ORR). A plausible mechanism is proposed for ORR that allows making use computational hydrogen electrode (CHE) approach this environment, suitable models have used estimate free-energy changes corresponding elementary steps. different analyzed terms electrochemical-step symmetry index (ESSI) Gmax descriptors. From these descriptors, Cu-containing SAC predicted exhibit highest catalytic activity which consistent a theoretical overpotential 0.71 V vs. standard (SHE) only, indicating type depolarized (ODCs) may overcome limitations high cost low abundance other precious metals.

Language: Английский

Citations

6
A general but still unknown characteristic of active oxygen evolution electrocatalysts DOI Creative Commons
Eleonora Romeo, Francesc Illas, Federico Calle‐Vallejo

et al.

Chemical Science, Journal Year: 2023, Volume and Issue: 14(13), P. 3622 - 3629

Published: Jan. 1, 2023

A common feature of active catalysts for oxygen evolution is that three their four electrochemical steps are over 1.23 eV. This evidences “electrochemical symmetry” a good criterion to design enhanced OER catalysts.

Language: Английский

Citations

16
Revised Nitrogen Reduction Scaling Relations from Potential-Dependent Modeling of Chemical and Electrochemical Steps DOI

Cooper Tezak,

Nicholas R. Singstock, Abdulaziz Alherz

et al.

ACS Catalysis, Journal Year: 2023, Volume and Issue: 13(19), P. 12894 - 12903

Published: Sept. 19, 2023

The electrochemical nitrogen reduction reaction (NRR) is a promising route to enable carbon-free ammonia production. However, this limited by the poor activity and selectivity of current catalysts. rational design superior NRR electrocatalysts requires detailed mechanistic understanding material limitations inform how these might be overcome. scaling limits on metal catalysts predicated simplified pathway that considers only proton-coupled electron transfer (PCET) steps. Here, we apply grand-canonical density functional theory investigate more comprehensive mechanism includes both chemical steps 30 surfaces in solvent under an applied potential. We Φmax, adaptation Gmax thermodynamic descriptor, evaluate trends catalyst activity. This approach produces Φmax "volcano" diagram for metals qualitatively differs from relations identified when PCET are considered. NH3* desorption was found limit materials at top volcano truncate volcano's peak increasingly reducing potentials. These revised may electrocatalysts. transferable study other chemistries where modeled

Language: Английский

Citations

16
Importance of the volcano slope to comprehend activity and selectivity trends in electrocatalysis DOI Creative Commons
Kai S. Exner

Current Opinion in Electrochemistry, Journal Year: 2023, Volume and Issue: 39, P. 101284 - 101284

Published: March 31, 2023

Volcano plots are a powerful tool to comprehend the trends of electrocatalysts from same class materials. While initially, it was considered that volcano slope is constant and single elementary reaction step governs rate at each leg, this well-accepted view challenged in present article. Taking oxygen reduction nitrogen reactions as case studies, reasons for non-constant rationalized on atomic scale by referring mechanistic diversity electrocatalytic processes application advanced activity descriptors, which go beyond evaluation free-energy change. Finally, implications discussed example four-electron two-electron reductions, demonstrating only consideration varying legs, obtained curves qualitative agreement with experimental observations.

Language: Английский

Citations

15
Refining Free-Energy Calculations for Electrochemical Reactions: Unveiling Corrections beyond Gas-Phase Errors for Solvated Species and Ions DOI Creative Commons
Ebrahim Tayyebi, Kai S. Exner

The Journal of Physical Chemistry C, Journal Year: 2024, Volume and Issue: 128(33), P. 13732 - 13742

Published: Aug. 9, 2024

As much of the theory related to computational electrocatalysis has been adapted from thermodynamics gas-phase reactions, it demands careful treatment and implementation proper corrections when investigating electrochemical systems. In this article, we present a comprehensive thermodynamic framework that incorporates all potential phases (gaseous or aqueous) different forms (molecular ionic) reactants products under ambient conditions. This elucidates systematic relationships governing Gibbs free energy across diverse chemical species, employing Henry's volatility constant (KHor H), acid dissociation (Ka), pH. We introduce method for calculating both KH Ka, detailing associated challenges. Our study demonstrates calculation energies is influenced by Ka pH, primarily due occurrence unbalanced numbers electrons protons transfers during adsorption desorption ions. findings also highlight inclusion aqueous products, whether in molecular ionic form, significantly modifies free-energy landscapes. turn, reported solvation ion are imperative obtain correct activity predictions descriptors such as overpotential span model Gmax(η), deviations more than 0.3 eV observed if these contributions ignored.

Language: Английский

Citations

5
Oxygen desorption – Critical step for the oxygen evolution reaction DOI Creative Commons
Tobias Binninger, Piotr M. Kowalski, Michael Eikerling

et al.

Current Opinion in Electrochemistry, Journal Year: 2023, Volume and Issue: 42, P. 101382 - 101382

Published: Sept. 1, 2023

The oxygen evolution reaction (OER) has been widely investigated in computational electrocatalysis. Recent studies suggest that the final desorption step could be rate-limiting, or even inhibiting, for classical OER mechanism on benchmark IrO2 electrocatalyst, and a novel proposed circumventing this bottleneck. In review, we provide an overview of recent progress electrocatalysis with concise focus explicitly accounted elementary O2 desorption. We highlight methodological intricacies led to not considering as crucial by earlier studies. Key suggestions are provided future open new directions

Language: Английский

Citations

12
Correlation between Electrocatalytic Activity and Impedance Shape: A Theoretical Analysis DOI Creative Commons
Jun Huang

PRX Energy, Journal Year: 2024, Volume and Issue: 3(2)

Published: April 9, 2024

Though electrochemical impedance spectroscopy (EIS) has been widely used in mechanistic investigations of electrocatalytic reactions, the correlation between shape an EIS diagram and activity is largely unclear; complexity reactions terms reaction mechanisms influencing factors casts air pessimism over existence and, if it exists, stability such a correlation. Nevertheless, understanding can help select electrical circuit models data analysis, use as descriptor activity, detect side measured shapes deviate from theoretical prediction based on main reaction. Herein, problem tackled by systematic mathematical analysis firstly single-adsorbate then more complicated involving multiple adsorbates. A complete regime all possible provided, navigating subsequent multidimensional parametric space. For two steps with identical transfer coefficients 0.5 absence lateral adsorbate interactions, several rigorous remarks are made. Unfortunately, many them require modifications when different interactions considered. trends robust against complexities variations parameters, which also receive experimental evidence collected literature. The presented here may trigger interest finding across wide range reactions. Published American Physical Society 2024

Language: Английский

Citations

4