TY - JOUR
T1 - Water Adsorption on MO2 (M = Ti, Ru, and Ir) Surfaces. Importance of Octahedral Distortion and Cooperative Effects
AU - González, Danilo
AU - Heras-Domingo, Javier
AU - Pantaleone, Stefano
AU - Rimola, Albert
AU - Rodríguez-Santiago, Luis
AU - Solans-Monfort, Xavier
AU - Sodupe, Mariona
N1 - Funding Information:
The authors gratefully acknowledge financial support from MINECO (CTQ2017-89132-P) and the Generalitat de Catalunya (2017SGR-1323). X.S.-M. is grateful for the Professor Agregat Serra Hunter position. A.R. is indebted to “Ramon y Cajal” program.
Publisher Copyright:
© Copyright 2019 American Chemical Society.
PY - 2019/2/11
Y1 - 2019/2/11
N2 - © Copyright 2019 American Chemical Society. Understanding metal oxide MO 2 (M = Ti, Ru, and Ir)-water interfaces is essential to assess the catalytic behavior of these materials. The present study analyzes the H 2 O-MO 2 interactions at the most abundant (110) and (011) surfaces, at two different water coverages: isolated water molecules and full monolayer, by means of Perdew-Burke-Ernzerhof-D2 static calculations and ab initio molecular dynamics (AIMD) simulations. Results indicate that adsorption preferably occurs in its molecular form on (110)-TiO 2 and in its dissociative form on (110)-RuO 2 and (110)-IrO 2 . The opposite trend is observed at the (011) facet. This different behavior is related to the kind of octahedral distortion observed in the bulk of these materials (tetragonal elongation for TiO 2 and tetragonal compression for RuO 2 and IrO 2 ) and to the different nature of the vacant sites created, axial on (110) and equatorial on (011). For the monolayer, additional effects such as cooperative H-bond interactions and cooperative adsorption come into play in determining the degree of deprotonation. For TiO 2 , AIMD indicates that the water monolayer is fully undissociated at both (110) and (011) surfaces, whereas for RuO 2 , water monolayer exhibits a 50% dissociation, the formation of H 3 O 2- motifs being essential. Finally, on (110)-IrO 2 , the main monolayer configuration is the fully dissociated one, whereas on (011)-IrO 2 , it exhibits a degree of dissociation that ranges between 50 and 75%. Overall, the present study shows that the degree of water dissociation results from a delicate balance between the H 2 O-MO 2 intrinsic interaction and cooperative hydrogen bonding and adsorption effects.
AB - © Copyright 2019 American Chemical Society. Understanding metal oxide MO 2 (M = Ti, Ru, and Ir)-water interfaces is essential to assess the catalytic behavior of these materials. The present study analyzes the H 2 O-MO 2 interactions at the most abundant (110) and (011) surfaces, at two different water coverages: isolated water molecules and full monolayer, by means of Perdew-Burke-Ernzerhof-D2 static calculations and ab initio molecular dynamics (AIMD) simulations. Results indicate that adsorption preferably occurs in its molecular form on (110)-TiO 2 and in its dissociative form on (110)-RuO 2 and (110)-IrO 2 . The opposite trend is observed at the (011) facet. This different behavior is related to the kind of octahedral distortion observed in the bulk of these materials (tetragonal elongation for TiO 2 and tetragonal compression for RuO 2 and IrO 2 ) and to the different nature of the vacant sites created, axial on (110) and equatorial on (011). For the monolayer, additional effects such as cooperative H-bond interactions and cooperative adsorption come into play in determining the degree of deprotonation. For TiO 2 , AIMD indicates that the water monolayer is fully undissociated at both (110) and (011) surfaces, whereas for RuO 2 , water monolayer exhibits a 50% dissociation, the formation of H 3 O 2- motifs being essential. Finally, on (110)-IrO 2 , the main monolayer configuration is the fully dissociated one, whereas on (011)-IrO 2 , it exhibits a degree of dissociation that ranges between 50 and 75%. Overall, the present study shows that the degree of water dissociation results from a delicate balance between the H 2 O-MO 2 intrinsic interaction and cooperative hydrogen bonding and adsorption effects.
KW - CATALYSTS
KW - DISSOCIATION
KW - DYNAMICS
KW - HREELS
KW - OXYGEN EVOLUTION REACTION
KW - RUO2(110)
KW - RUTILE
KW - SITES
KW - STABILITY
KW - TIO2(110)
UR - http://www.scopus.com/inward/record.url?scp=85061613283&partnerID=8YFLogxK
U2 - https://doi.org/10.1021/acsomega.8b03350
DO - https://doi.org/10.1021/acsomega.8b03350
M3 - Article
C2 - 31459524
VL - 4
SP - 2989
EP - 2999
IS - 2
ER -