Dimerization induced deprotonation of water on RuO2(110)

Rentao Mu; David C. Cantu; Xiao Lin; Vassiliki Alexandra Glezakou; Zhitao Wang; Igor Lyubinetsky; Roger Rousseau; Zdenek Dohnálek

doi:10.1021/jz501810g

Dimerization induced deprotonation of water on RuO₂(110)

Rentao Mu, David C. Cantu, Xiao Lin, Vassiliki Alexandra Glezakou, Zhitao Wang, Igor Lyubinetsky, Roger Rousseau, Zdenek Dohnálek

Research output: Contribution to journal › Article › peer-review

50 Scopus citations

Abstract

RuO₂ has proven to be indispensable as a co-catalyst in numerous systems designed for photocatalytic water splitting. In this study, we have carried out a detailed mechanistic study of water behavior on the most stable RuO₂ face, RuO₂(110), by employing variable-temperature scanning tunneling microscopy and density functional theory calculations. We show that water monomers adsorb molecularly on Ru sites, become mobile above 238 K, diffuse along the Ru rows, and form water dimers. The onset for dimer diffusion is observed at ∼277 K, indicating a significantly higher diffusion barrier than that for monomers. More importantly, we find that water dimers deprotonate readily to form Ru-bound H₃O₂ and bridging OH species. The observed behavior is compared and contrasted with that observed for water on isostructural rutile TiO₂(110).

Original language	English
Pages (from-to)	3445-3450
Number of pages	6
Journal	Journal of Physical Chemistry Letters
Volume	5
Issue number	19
DOIs	https://doi.org/10.1021/jz501810g
State	Published - Oct 2 2014
Externally published	Yes

Funding

Funders	Funder number
U.S. Department of Energy

Keywords

adsorption
density functional theory
diffusion
scanning tunneling microscopy
water splitting

Access to Document

10.1021/jz501810g

Cite this

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title = "Dimerization induced deprotonation of water on RuO2(110)",

abstract = "RuO2 has proven to be indispensable as a co-catalyst in numerous systems designed for photocatalytic water splitting. In this study, we have carried out a detailed mechanistic study of water behavior on the most stable RuO2 face, RuO2(110), by employing variable-temperature scanning tunneling microscopy and density functional theory calculations. We show that water monomers adsorb molecularly on Ru sites, become mobile above 238 K, diffuse along the Ru rows, and form water dimers. The onset for dimer diffusion is observed at ∼277 K, indicating a significantly higher diffusion barrier than that for monomers. More importantly, we find that water dimers deprotonate readily to form Ru-bound H3O2 and bridging OH species. The observed behavior is compared and contrasted with that observed for water on isostructural rutile TiO2(110).",

keywords = "adsorption, density functional theory, diffusion, scanning tunneling microscopy, water splitting",

author = "Rentao Mu and Cantu, {David C.} and Xiao Lin and Glezakou, {Vassiliki Alexandra} and Zhitao Wang and Igor Lyubinetsky and Roger Rousseau and Zdenek Dohn{\'a}lek",

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AU - Mu, Rentao

AU - Cantu, David C.

AU - Lin, Xiao

AU - Glezakou, Vassiliki Alexandra

AU - Wang, Zhitao

AU - Lyubinetsky, Igor

AU - Rousseau, Roger

AU - Dohnálek, Zdenek

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AB - RuO2 has proven to be indispensable as a co-catalyst in numerous systems designed for photocatalytic water splitting. In this study, we have carried out a detailed mechanistic study of water behavior on the most stable RuO2 face, RuO2(110), by employing variable-temperature scanning tunneling microscopy and density functional theory calculations. We show that water monomers adsorb molecularly on Ru sites, become mobile above 238 K, diffuse along the Ru rows, and form water dimers. The onset for dimer diffusion is observed at ∼277 K, indicating a significantly higher diffusion barrier than that for monomers. More importantly, we find that water dimers deprotonate readily to form Ru-bound H3O2 and bridging OH species. The observed behavior is compared and contrasted with that observed for water on isostructural rutile TiO2(110).

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KW - diffusion

KW - scanning tunneling microscopy

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