Hydrogen motion in rutile TiO2

Hupfer, A.; Monakhov, E. V.; Svensson, B. G.; Chaplygin, I.; Lavrov, E. V.

doi:10.1038/s41598-017-16660-3

Cited by 19 publications

(26 citation statements)

References 52 publications

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“…This finding demonstrates the strong anisotropy in the migration of hydrogen and agrees with the existing experimental diffusion data [15,38]. More specifically, the energy barrier E barr for the proton-transfer T3 path is extremely high (2.30 eV), very likely owing to the rather large hopping length for hydrogen (equal to 2.89 Å).…”

Section: Atomistic Mechanisms Of Hydrogen Migrationsupporting

confidence: 89%

“…The present results for E a slightly underestimate the experimentally derived activation energies of hydrogen diffusion parallel to the c axis: an activation energy of 0.59 eV was obtained by Johnson et al [15] from high-temperature diffusion data (the temperature range was from 350°C-700 °C). A recent work has extended diffusion measurements to lower temperatures (from 157 K to 197 K) by studying stressed-induced dichroism of the local vibrational modes due to hydrogen and deuterium [38]. These authors reported an overall activation energy equal to 0.54 eV by combining high-temperature and low-temperature data.…”

Section: Diffusion Rate and Coefficient Along The C Axismentioning

confidence: 99%

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Electronic structure and migration of interstitial hydrogen in the rutile phase of TiO₂

Marinopoulos¹,

Vilão²,

Alberto³

et al. 2018

J. Phys.: Condens. Matter

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The formation and migration energies of interstitial hydrogen in rutile TiO are obtained from first principles calculations. The computational approach was based on density functional theory with a semilocal generalised-gradient approximation functional, supplemented with an on-site Hubbard term to account for correlation among the Ti 3d electrons. Charge-transition levels are calculated and compared to previous theoretical studies. The donor character of hydrogen is examined in depth, focusing in particular on the tendency to form polaron-like configurations with the unpaired electron trapped at nearby titanium ions. Distinct minimum-energy paths of hydrogen migration and associated energy barriers were determined by the nudged elastic-band method. The present findings show clearly the strong anisotropy in the energy barriers for migration within the open c channels as opposed to migration crossing adjacent channels of the rutile lattice. For the rate-limiting step which leads to macroscopic diffusion along the c axis the corresponding rate and diffusion coefficient were also determined from transition-state theory. The results are discussed in connection to existing measurements of hydrogen diffusion and recent findings from electron paramagnetic resonance, electron-nuclear double resonance and muonium spectroscopies that probed the spatial localization of the electron spin.

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Section: Atomistic Mechanisms Of Hydrogen Migrationsupporting

confidence: 89%

Section: Diffusion Rate and Coefficient Along The C Axismentioning

confidence: 99%

Electronic structure and migration of interstitial hydrogen in the rutile phase of TiO₂

Marinopoulos¹,

Vilão²,

Alberto³

et al. 2018

J. Phys.: Condens. Matter

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“…Relatively simple theoretical model with single V O and single H* is presented here. Previous reports show that applied strain effects diffusion pathways and overall distribution of H*s on rutile TiO 2 53,56 . Strain also affects formation, diffusion and energy of V O s, as discussed throughout the text.…”

Section: Resultsmentioning

confidence: 95%

Dynamic Tuning of a Thin Film Electrocatalyst by Tensile Strain

Benson

Gregg

et al. 2019

Sci Rep

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We report the ability to tune the catalytic activities for the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) by applying mechanical stress on a highly n-type doped rutile TiO2 films. We demonstrate through operando electrochemical experiments that the low HER activity of TiO2 can reversibly approach those of the state-of-the-art non-precious metal catalysts when the TiO2 is under tensile strain. At 3% tensile strain, the HER overpotential required to generate a current density of 1 mA/cm2 shifts anodically by 260 mV to give an onset potential of 125 mV, representing a drastic reduction in the kinetic overpotential. A similar albeit smaller cathodic shift in the OER overpotential is observed when tensile strain is applied to TiO2. Results suggest that significant improvements in HER and OER activities with tensile strain are due to an increase in concentration of surface active sites and a decrease in kinetic and thermodynamics barriers along the reaction pathway(s). Our results highlight that strain applied to TiO2 by precisely controlled and incrementally increasing (i.e. dynamic) tensile stress is an effective tool for dynamically tuning the electrocatalytic properties of HER and OER electrocatalysts relative to their activities under static conditions.

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“…Moreover, H is also likely to form complexes with various other defects [232]. Notably, H has a large diffusion coefficient in r-TiO 2 [241], and it has been shown that H can in-diffuse into r-TiO 2 during heat-treatments even if H is only present as a residual impurity in the annealing atmosphere [125].…”

Section: Defects In Rutile Titanium Dioxidementioning

confidence: 99%

Ti- and Fe-related charge transition levels in β−Ga2O3

Zimmermann

Frodason

Barnard

et al. 2020

Applied Physics Letters

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This thesis would not have been possible without the support of many people, and I am eternally grateful for all the support. I hope to see some of you again in the future! The main objective of my PhD project was to study defects in semiconducting oxides within the research project FOXHOUND headed by Prof. Lasse Vines, my main supervisor. I am grateful to Lasse for the opportunity to work on this topic. I have learned much more than I imagined I would when I started. Lasse, you have been a patient and competent supervisor who always took time to answer endless streams of questions. Prof. Truls Norby and Assoc. Prof. Anette Eleonora Gunnaes were co-advisors for my PhD project. I am grateful to Truls for introducing me to the chemist's view on defects and his group FASE/ELCHEM. I am truly sad that I did not get to collaborate more with Anette. I also want to thank Prof. Eduard Monakhov and the late Prof. Bengt Gunnar Svensson. Both were valuable unofficial advisers on my PhD, and helped moving my work along. Most of my work was carried out within the semiconductor physics group at the University of Oslo (LENS), and I would like to thank of all its current and former members for contributing to my work in many ways. There are some people who deserve special thanks. First of all, I am grateful to my long-term office mates Torunn, Sigbjørn and Josef for sharing many conversations and being there for each other. Secondly, I am particularly grateful to all my close collaborators at LENS, and especially Julie, Philip, Ymir, Vegard R., Vegard O., Viktor and Espen. I also want to thank our engineers (Micke, Halvor, Christoph and Viktor) and administrative staff (Marit, Heine and Kristin) for keeping things running! Also, thanks to Ilia, Robert, Vegard R. and Jon for taking care of the needs of the E-Lab and the Online-Setup. I was a co-supervisor for two master students: Vegard R. and Espen. I hope both of them learned something from me, because I did definitely learn from them. I am particularly grateful to Vegard R. for being a large part in building the steady-state photo-capacitance setup used in this work. I also would like to thank all my co-authors from outside of Oslo: Frank from Dresden, Willem, Walter and Danie from Pretoria, Klaus and Zbigniew from Berlin, Antti from Aalto and Joel from California. Special thanks to Willem, Walter and Danie for hosting me in Pretoria and showing me around. Last but not least, I would like to thank my family and my friends for their support!

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Hydrogen motion in rutile TiO2

Cited by 19 publications

References 52 publications

Electronic structure and migration of interstitial hydrogen in the rutile phase of TiO₂

Electronic structure and migration of interstitial hydrogen in the rutile phase of TiO₂

Dynamic Tuning of a Thin Film Electrocatalyst by Tensile Strain

Ti- and Fe-related charge transition levels in β−Ga2O3

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Hydrogen motion in rutile TiO2

Cited by 19 publications

References 52 publications

Electronic structure and migration of interstitial hydrogen in the rutile phase of TiO2

Electronic structure and migration of interstitial hydrogen in the rutile phase of TiO2

Dynamic Tuning of a Thin Film Electrocatalyst by Tensile Strain

Ti- and Fe-related charge transition levels in β−Ga2O3

Contact Info

Product

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About

Electronic structure and migration of interstitial hydrogen in the rutile phase of TiO₂

Electronic structure and migration of interstitial hydrogen in the rutile phase of TiO₂