scholarly journals Grand-canonical approach to density functional theory of electrocatalytic systems: Thermodynamics of solid-liquid interfaces at constant ion and electrode potentials

2019 ◽  
Vol 150 (4) ◽  
pp. 041706 ◽  
Author(s):  
Marko M. Melander ◽  
Mikael J. Kuisma ◽  
Thorbjørn Erik Køppen Christensen ◽  
Karoliina Honkala
Keyword(s):  
Density Functional Theory ◽  
Density Functional ◽  
Liquid Interfaces ◽  
Functional Theory ◽  
Electrode Potentials ◽  
Canonical Approach ◽  
Solid Liquid ◽  
Grand Canonical

scholarly journals Grand-Canonical Approach to Density Functional Theory of Electrocatalytic Systems: Thermodynamics of Solid-Liquid Interfaces at Constant Ion and Electrode Potentials

2018 ◽  
Author(s):  
Marko Melander ◽  
Mikael Kuisma ◽  
Thorbjørn Christensen ◽  
Karoliina Honkala
Keyword(s):  
Density Functional ◽  
Canonical Ensemble ◽  
Coarse Graining ◽  
Grand Canonical Ensemble ◽  
Liquid Interfaces ◽  
Functional Theory ◽  
Electrode Potentials ◽  
Solid Liquid ◽  
Electrochemical Interfaces ◽  
Grand Canonical

Properties of solid-liquid interfaces are of immense importance for electrocatalytic and electrochemical systems but modelling such interfaces at the atomic level presents a serious challenge and approaches beyond standard methodologies are needed. An atomistic computational scheme needs treat at least part of the system quantum mechanically to include adsorption and reactions while the entire system is in thermal equilibrium. The experimentally relevant macroscopic control variables are temperature, electrode potential, choice of the solvent and ions and these need to be explicitly included in the computational model as well; this calls for an thermodynamic ensemble with fixed ion and electrode potentials. In this work a general framework within density functional theory with fixed electron and ion chemical potentials in the grand canonical ensemble is established for modelling electrocatalytic and electrochemical interfaces. Starting from a fully quantum mechanical description of nuclei and electrons, a systematic coarse-graining is employed to establish various computational schemes including i) the combination of classical and electronic density functional theories within the grand canonical ensemble and ii) on the simplest level a chemically and physically sound way to obtain the (modified) Poisson-Boltzmann (mPB) implicit solvent model. The detailed and rigorous derivation clearly establishes which approximations are needed for coarse-graining as well as highlights which details and interactions are omitted in vein of computational feasibility. The transparent approximations also allow removing some the constraints and coarse-graining if needed. We implement various mPB models in the GPAW code and test their capabilities to model capacitance of electrochemical interfaces as well as study different approaches for modelling partly periodic charged systems. Our rigorous and well-defined DFT coarse-graining scheme to continuum electrolytes highlights the inadequacy of current linear dielectric models for treating properties of the electrochemical interface.<br><br>

scholarly journals Grand-Canonical Approach to Density Functional Theory of Electrocatalytic Systems: Thermodynamics of Solid-Liquid Interfaces at Constant Ion and Electrode Potentials

2018 ◽  
Author(s):  
Marko Melander ◽  
Mikael Kuisma ◽  
Thorbjørn Christensen ◽  
Karoliina Honkala
Keyword(s):  
Density Functional ◽  
Canonical Ensemble ◽  
Coarse Graining ◽  
Grand Canonical Ensemble ◽  
Liquid Interfaces ◽  
Functional Theory ◽  
Electrode Potentials ◽  
Solid Liquid ◽  
Electrochemical Interfaces ◽  
Grand Canonical

Properties of solid-liquid interfaces are of immense importance for electrocatalytic and electrochemical systems but modelling such interfaces at the atomic level presents a serious challenge and approaches beyond standard methodologies are needed. An atomistic computational scheme needs treat at least part of the system quantum mechanically to include adsorption and reactions while the entire system is in thermal equilibrium. The experimentally relevant macroscopic control variables are temperature, electrode potential, choice of the solvent and ions and these need to be explicitly included in the computational model as well; this calls for an thermodynamic ensemble with fixed ion and electrode potentials. In this work a general framework within density functional theory with fixed electron and ion chemical potentials in the grand canonical ensemble is established for modelling electrocatalytic and electrochemical interfaces. Starting from a fully quantum mechanical description of nuclei and electrons, a systematic coarse-graining is employed to establish various computational schemes including i) the combination of classical and electronic density functional theories within the grand canonical ensemble and ii) on the simplest level a chemically and physically sound way to obtain the (modified) Poisson-Boltzmann (mPB) implicit solvent model. The detailed and rigorous derivation clearly establishes which approximations are needed for coarse-graining as well as highlights which details and interactions are omitted in vein of computational feasibility. The transparent approximations also allow removing some the constraints and coarse-graining if needed. We implement various mPB models in the GPAW code and test their capabilities to model capacitance of electrochemical interfaces as well as study different approaches for modelling partly periodic charged systems. Our rigorous and well-defined DFT coarse-graining scheme to continuum electrolytes highlights the inadequacy of current linear dielectric models for treating properties of the electrochemical interface.<br><br>

scholarly journals Grand-Canonical Approach to Density Functional Theory of Electrocatalytic Systems: Thermodynamics of Solid-Liquid Interfaces at Constant Ion and Electrode Potentials

2018 ◽  
Author(s):  
Marko Melander ◽  
Mikael Kuisma ◽  
Thorbjørn Christensen ◽  
Karoliina Honkala
Keyword(s):  
Density Functional ◽  
Canonical Ensemble ◽  
Coarse Graining ◽  
Grand Canonical Ensemble ◽  
Liquid Interfaces ◽  
Functional Theory ◽  
Electrode Potentials ◽  
Solid Liquid ◽  
Electrochemical Interfaces ◽  
Grand Canonical

Properties of solid-liquid interfaces are of immense importance for electrocatalytic and electrochemical systems but modelling such interfaces at the atomic level presents a serious challenge and approaches beyond standard methodologies are needed. An atomistic computational scheme needs treat at least part of the system quantum mechanically to include adsorption and reactions while the entire system is in thermal equilibrium. The experimentally relevant macroscopic control variables are temperature, electrode potential, choice of the solvent and ions and these need to be explicitly included in the computational model as well; this calls for an thermodynamic ensemble with fixed ion and electrode potentials. In this work a general framework within density functional theory with fixed electron and ion chemical potentials in the grand canonical ensemble is established for modelling electrocatalytic and electrochemical interfaces. Starting from a fully quantum mechanical description of nuclei and electrons, a systematic coarse-graining is employed to establish various computational schemes including i) the combination of classical and electronic density functional theories within the grand canonical ensemble and ii) on the simplest level a chemically and physically sound way to obtain the (modified) Poisson-Boltzmann (mPB) implicit solvent model. The detailed and rigorous derivation clearly establishes which approximations are needed for coarse-graining as well as highlights which details and interactions are omitted in vein of computational feasibility. The transparent approximations also allow removing some the constraints and coarse-graining if needed. We implement various mPB models in the GPAW code and test their capabilities to model capacitance of electrochemical interfaces as well as study different approaches for modelling partly periodic charged systems. Our rigorous and well-defined DFT coarse-graining scheme to continuum electrolytes highlights the inadequacy of current linear dielectric models for treating properties of the electrochemical interface.<br><br>

Ruthenium single-atom catalysis for electrocatalytic nitrogen reduction unveiled by grand canonical density functional theory

2020 ◽  
Vol 8 (39) ◽  
pp. 20402-20407
Author(s):  
Yujin Ji ◽  
Yifan Li ◽  
Huilong Dong ◽  
Lifeng Ding ◽  
Youyong Li
Keyword(s):  
Density Functional Theory ◽  
Density Functional ◽  
Density Functional Theory Calculations ◽  
Catalytic Site ◽  
Single Atom ◽  
Functional Theory ◽  
Nitrogen Reduction ◽  
Grand Canonical

Grand canonical density functional theory calculations reveal that the Ru–N4 motif is the superior catalytic site for eNRR rather than the Ru–N3 motif.

scholarly journals The interface of SrTiO 3 and H 2 O from density functional theory molecular dynamics

2016 ◽  
Vol 472 (2193) ◽  
pp. 20160293 ◽  
Author(s):  
E. Holmström ◽  
P. Spijker ◽  
A. S. Foster
Keyword(s):  
Molecular Dynamics ◽  
Density Functional Theory ◽  
Density Functional ◽  
Liquid Interface ◽  
Strong Suppression ◽  
Electronic Density ◽  
Functional Theory ◽  
Degree Of Dissociation ◽  
Solid Liquid Interface ◽  
Solid Liquid

We use dispersion-corrected density functional theory molecular dynamics simulations to predict the ionic, electronic and vibrational properties of the SrTiO 3 /H 2 O solid–liquid interface. Approximately 50% of surface oxygens on the planar SrO termination are hydroxylated at all studied levels of water coverage, the corresponding number being 15% for the planar TiO 2 termination and 5% on the stepped TiO 2 -terminated surface. The lateral ordering of the hydration structure is largely controlled by covalent-like surface cation to H 2 O bonding and surface corrugation. We find a featureless electronic density of states in and around the band gap energy region at the solid–liquid interface. The vibrational spectrum indicates redshifting of the O–H stretching band due to surface-to-liquid hydrogen bonding and blueshifting due to high-frequency stretching vibrations of OH fragments within the liquid, as well as strong suppression of the OH stretching band on the stepped surface. We find highly varying rates of proton transfer above different SrTiO 3 surfaces, owing to differences in hydrogen bond strength and the degree of dissociation of incident water. Trends in proton dynamics and the mode of H 2 O adsorption among studied surfaces can be explained by the differential ionicity of the Ti–O and Sr–O bonds in the SrTiO 3 crystal.

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