Phase Stability and Phase Structure of Ru–Ti–O Complex Oxide Electrocatalyst

Wang, Xin; Shao, Yanqun; Liu, Xuehua; Tang, Dian; Wu, Bo; Tang, Zhenwei; Lin, Wei

doi:10.1111/jace.13398

Cited by 15 publications

(13 citation statements)

References 49 publications

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“…Structural data from Rietveld fitting for the RuO 2 sample indicated the presence of a single phase with lattice parameters a = b = 4.490 Å and c = 3.086 Å. This structure was in good agreement with the calculated parameters determined by DFT, a = b = 4.487 Å and c = 3.108 Å, and those reported in the literature. − The Ru 1– x Ti x O 2 ( x = 0, 12.5, 20, and 50 at. %) samples showed the presence of two phases, one of which was in a lower proportion of 2–14% (Table S3).…”

Section: Resultssupporting

confidence: 82%

Titanium Substitution Effects on the Structure, Activity, and Stability of Nanoscale Ruthenium Oxide Oxygen Evolution Electrocatalysts: Experimental and Computational Study

Godínez-Salomón

Ospina-Acevedo

Albiter

et al. 2022

ACS Appl. Nano Mater.

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Proton-exchange membrane water electrolyzers produce hydrogen from water and electricity and can be powered using renewable energy; however, the high overpotential, high cost, and limited supply of the oxygen evolution reaction (OER) electrocatalyst are key factors that hinder wide-scale adoption. Ruthenium oxide (RuO2) has a lower overpotential, lower cost, and higher global supply compared with iridium oxide (IrO2), but RuO2 is less stable than IrO2. As an approach to improve the catalytic stability, we report the effect of titanium substitution at different concentrations within nanoscale RuO2, Ru1–x Ti x O2 (x = 0–50 at. %), on the structure, OER activity, and stability using combined experiments and theory. Titanium substitution within rutile RuO2 affects the electronic structure, resulting in regions of electron accumulation and electron depletion at the surface, and shifts the d-band and O 2p band centers to higher binding energies. Calculations show that the effects of Ti on the electronic structure are highly dependent on not only the concentration but also the specific dopant location. From electrochemical testing and analysis of the electrolyte and simulations, titanium substitution at low concentrations (12.5 and 20 at. %) improves catalyst stability and lowers Ru dissolution. Experiments of OER activity agree with the theory that Ti substitution results in a higher overpotential when averaging over all adsorption sites. Theoretical analysis shows that specific sites predominately act as catalytic sites for the OER, while metal dissolution occurs at different sites. Specifically, OER has the lowest barriers at penta-coordinated Ru sites, while hexa-coordinated Ru sites have the lowest energetic barriers for dissolution.

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Section: Resultssupporting

confidence: 82%

Titanium Substitution Effects on the Structure, Activity, and Stability of Nanoscale Ruthenium Oxide Oxygen Evolution Electrocatalysts: Experimental and Computational Study

Godínez-Salomón

Ospina-Acevedo

Albiter

et al. 2022

ACS Appl. Nano Mater.

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“…The mixed oxides were prepared by thermal decomposition of precursors mixtures, exactly reproducing the preparation used by Bandi et al in their works. , It is established that mixed Ru–Sn oxides monophasic solid solutions can be prepared over the whole composition range . In contrast, the crystal structure of mixed Ru–Ti oxide is the subject of controversy. , Several studies on Ru–Ti oxide prepared via thermal decomposition (the same procedure used in our work) postulate the formation of a (meta)stable solid solution for a large compositional window. , In contrast, oxides prepared via sol–gel routes tend to result in two separate phases . Our XRD results (Figure S11) showed the formation of a monophasic solid solution for Ru–Sn oxides and for Ru:Ti of 50:50 (at:at), while a biphasic structure was formed increasing the Ti content (Ru:Ti of 25:75).…”

Section: Resultsmentioning

confidence: 58%

“…37 In contrast, the crystal structure of mixed Ru−Ti oxide is the subject of controversy. 38,39 Several studies on Ru−Ti oxide prepared via thermal decomposition (the same procedure used in our work) postulate the formation of a (meta)stable solid solution for a large compositional window. 38,40 In contrast, oxides prepared via sol−gel routes tend to result in two separate phases.…”

Section: ■ Results and Discussionmentioning

confidence: 87%

“…38,39 Several studies on Ru−Ti oxide prepared via thermal decomposition (the same procedure used in our work) postulate the formation of a (meta)stable solid solution for a large compositional window. 38,40 In contrast, oxides prepared via sol−gel routes tend to result in two separate phases. 41 Our XRD results (Figure S11) showed the formation of a monophasic solid solution for Ru−Sn oxides and for Ru:Ti of 50:50 (at:at), while a biphasic structure was formed increasing the Ti content (Ru:Ti of 25:75).…”

Section: ■ Results and Discussionmentioning

confidence: 87%

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Activity–or Lack Thereof–of RuO₂-Based Electrodes in the Electrocatalytic Reduction of CO₂

Mezzavilla

Katayama

Rao³

et al. 2019

J. Phys. Chem. C

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“…However, the calculated critical composition point of 0.538 is slightly inconsistent with the two‐phase dissolution deviation. Wang et al have studied the Ru 1− x Ti x O 2 solid solution by means of experiment and theoretical calculation. They modified the temperature‐dependent interaction parameters to describe the larger critical component point, and found that the excessive critical temperature (3939 K) leads to the narrow range of single‐phase solid solution in the phase diagram.…”

Section: Introductionmentioning

confidence: 99%

Stable structure and electronic properties of Ru₁₋_xTi_xO₂ rutile type solid solutions from DFT calculations

Yang

Zhao

2019

J Am Ceram Soc

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To design solid solution is an effective strategy for functional materials. The complex electron correlation and non‐equilibrium atomic interaction are the primary factors to impact the macro‐/micro‐structure and application performances of solid solution. Hence, this article concentrates on the stable crystal structure and the corresponding electronic structure of Ru1−xTixO2 solid solution by using density functional theory calculations. Based on analyzing the atomic interaction between solute and solvent atoms, the most stable supercell models for the specific solid solubility were obtained. In Ru1−xTixO2 solid solution, solute (and solvent) atoms preferentially arrange along the [110] direction, and tend to occupy the nearest sites of identical atoms, to arrange the symmetric ordered substitution configurations. Using the subregular solution model, the mixing enthalpy can be represented by the following expression: ΔHf=XTiO2XRuO235.30XTiO2+23.08XRuO2. The calculated phase diagram is consistent with the experimental results. Thus, the calculated results in this article are reliable and can provide more meaningful information. In the cases of Ru‐rich solid solutions, the metastable phase exists in the range of x < 0.27; while in the cases of Ti‐rich solid solutions, the metastable phase exists in the range of x > 0.81. Interestingly, the electron density of Ru1−xTixO2 solid solutions at Fermi level has a stronger dependence on the Ru composition, which intrinsically influences its electronic structure and optical properties. According to the basic application principle, Ru1−xTixO2 solid solutions with lower (x < 0.27) and higher (x > 0.81) solid solubility could act as suitable candidate for the applications in field electrochemistry and photocatalysis.

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Phase Stability and Phase Structure of Ru–Ti–O Complex Oxide Electrocatalyst

Cited by 15 publications

References 49 publications

Titanium Substitution Effects on the Structure, Activity, and Stability of Nanoscale Ruthenium Oxide Oxygen Evolution Electrocatalysts: Experimental and Computational Study

Titanium Substitution Effects on the Structure, Activity, and Stability of Nanoscale Ruthenium Oxide Oxygen Evolution Electrocatalysts: Experimental and Computational Study

Activity–or Lack Thereof–of RuO₂-Based Electrodes in the Electrocatalytic Reduction of CO₂

Stable structure and electronic properties of Ru₁₋_xTi_xO₂ rutile type solid solutions from DFT calculations

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Phase Stability and Phase Structure of Ru–Ti–O Complex Oxide Electrocatalyst

Cited by 15 publications

References 49 publications

Titanium Substitution Effects on the Structure, Activity, and Stability of Nanoscale Ruthenium Oxide Oxygen Evolution Electrocatalysts: Experimental and Computational Study

Titanium Substitution Effects on the Structure, Activity, and Stability of Nanoscale Ruthenium Oxide Oxygen Evolution Electrocatalysts: Experimental and Computational Study

Activity–or Lack Thereof–of RuO2-Based Electrodes in the Electrocatalytic Reduction of CO2

Stable structure and electronic properties of Ru1−xTixO2 rutile type solid solutions from DFT calculations

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Product

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Activity–or Lack Thereof–of RuO₂-Based Electrodes in the Electrocatalytic Reduction of CO₂

Stable structure and electronic properties of Ru₁₋_xTi_xO₂ rutile type solid solutions from DFT calculations