Structure and reactivity of a water-covered anatase TiO<sub>2</sub>(001) surface

Lang, Xiufeng; Liang, Yan; Zhang, Jing; Li, Lei; Cao, Liqin; Zhang, Hongsheng

doi:10.1039/c9cp05409j

Cited by 17 publications

(9 citation statements)

References 63 publications

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“…These results are in line with several theoretical ndings in the literature. [35][36][37] As RH increases, a hierarchical ice-like water layer starts forming on the top of the chemisorbed layer on {001} and {100} facets. On the {101} surface, the incoming water molecules rst bond to O 2c , 30 and then to the surface adsorbed H 2 O with hydrogen bonds are not as strong as those on the {001} and {100} facets where water molecules form hydrogen bonds with the surface -OH groups.…”

Section: Structure Characterizationmentioning

confidence: 99%

Facet-engineered TiO₂ nanomaterials reveal the role of water–oxide interactions in surface protonic conduction

et al. 2022

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Section: Structure Characterizationmentioning

confidence: 99%

Facet-engineered TiO₂ nanomaterials reveal the role of water–oxide interactions in surface protonic conduction

et al. 2022

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“…When reducing the TNTAs in a 5% H 2 /Ar atmosphere, oxygen vacancies are introduced, as shown by XPS and DRS/PL earlier, that can be responsible for improving both the conductivity and the visible light response . In addition, both theoretical calculations and experimental results have shown that oxygen vacancies on TiO 2 surfaces enhance adsorption and dissociation of water molecules, ultimately increasing the surface protonic conduction. − It increases the performance of the photoanode also by increasing the concentration of reactants for water splitting.…”

Section: Results and Discussionmentioning

confidence: 99%

Water Vapor Photoelectrolysis in a Solid-State Photoelectrochemical Cell with TiO₂ Nanotubes Loaded with CdS and CdSe Nanoparticles

Kang

Chaperman

Galeckas

et al. 2021

ACS Appl. Mater. Interfaces

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In this study, polyol-made CdS and CdSe crystalline nanoparticles (NPs) are loaded by impregnation on TiO 2 nanotube arrays (TNTAs) for solar-simulated light-driven photoelectrochemical (PEC) water vapor splitting. For the first time, we introduce a safe way to utilize toxic, yet efficient photocatalysts by integration in solid-state PEC (SSPEC) cells. The enabling features of SSPEC cells are the surface protonic conduction mechanism on TiO 2 and the use of polymeric electrolytes, such as Nafion instead of liquid ones, for operation with gaseous reactants, like water vapor from ambient humidity. Herein, we studied the effects of both the operating conditions in gaseous ambient atmospheres and the surface modifications of TNTAs-based photoanodes with well-crystallized CdS and CdSe NPs. We showed 3.6 and 2.5 times increase in the photocurrent density of defective TNTAs modified with CdS and CdSe, respectively, compared to the pristine TNTAs. Electrochemical impedance spectroscopy and structural characterizations attributed the improved performance to the higher conductivity induced by intrinsic defects as well as to the enhanced electron/hole separation at the TiO 2 /CdS heterojunction under gaseous operating conditions. The SSPEC cells were evaluated by cycling between high relative humidity (RH) (80%) and low RH levels (40%), providing direct evidence of the effect of RH and, in turn, adsorbed water, on the cell performance. Online mass spectrometry indicated the corresponding difference in the H 2 production rate. In addition, a complete restoration of the SSPEC cell performance from low to high RH levels was also achieved. The presented system can be employed in off-grid, water depleted, and air-polluted areas for the production of hydrogen from renewable energy and provides a solution for the safe use of toxic, yet efficient photocatalysts.

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“…Previous theoretical studies have found that water adsorption on A-001 leads to formation of a monolayer of mixed molecular-dissociated molecules on both the bulk-terminated and (1 × 4) reconstructed surfaces. 22,44 On the latter, water dissociation takes place on the ridges and gives rise to a 3-fold periodicity along the ridge direction. 17 In our simulation, water dissociation on the ridges leads to a twinprotrusion structure (Figure 2, middle panel), similar to that observed in a recent transmission electron microscopy study of reconstructed A-001 exposed to water vapor.…”

Section: Stability Of Reconstructed A-001 (1 × 4) Inmentioning

confidence: 99%

Structure and Stability of Pristine and Carboxylate-Covered Anatase TiO₂(001) in Aqueous Environment

2021

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The interactions of carboxylic acids and water with TiO 2 surfaces are important in applications ranging from solar cells to biomedical devices. Here we focus on the aqueous interface with the minority (001) surface of anatase TiO 2 (A-001) and the behavior of adsorbed formic and acetic acid monolayers at this interface. We investigated the structure and stability of the pristine reconstructed and formic/acetic acid covered A-001 surfaces in contact with water using density functional theory (DFT) calculations and ab initio molecular dynamics (AIMD) simulations. The (1 × 4) reconstruction of the pristine surface is found to be stable in aqueous environment, within the time scale of our simulation. Carboxylic acids adsorb in deprotonated bidentate (BD) form on A-001, with the dissociated proton transferred to a surface oxygen to form a bridging hydroxyl. Of the two possible configurations, BD bridging and BD straddling, of the adsorbed species, the latter is found to rapidly transform to a monodentate structure during our simulations. Further investigation of mixed acetate−formate monolayers on A-001 in water indicates that also BD bridging species can become unstable at the boundaries between formate and acetate-covered regions, transforming to a monodentate form that does not prevent water adsorption on the TiO 2 surface.

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Structure and reactivity of a water-covered anatase TiO₂(001) surface

Abstract: We systematically studied water adsorption and oxidation on the unreconstructed TiO2(001) surface using first-principles calculations.

Cited by 17 publications

References 63 publications

Facet-engineered TiO₂ nanomaterials reveal the role of water–oxide interactions in surface protonic conduction

Facet-engineered TiO₂ nanomaterials reveal the role of water–oxide interactions in surface protonic conduction

Water Vapor Photoelectrolysis in a Solid-State Photoelectrochemical Cell with TiO₂ Nanotubes Loaded with CdS and CdSe Nanoparticles

Structure and Stability of Pristine and Carboxylate-Covered Anatase TiO₂(001) in Aqueous Environment

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Structure and reactivity of a water-covered anatase TiO2(001) surface

Abstract: We systematically studied water adsorption and oxidation on the unreconstructed TiO2(001) surface using first-principles calculations.

Cited by 17 publications

References 63 publications

Facet-engineered TiO2 nanomaterials reveal the role of water–oxide interactions in surface protonic conduction

Facet-engineered TiO2 nanomaterials reveal the role of water–oxide interactions in surface protonic conduction

Water Vapor Photoelectrolysis in a Solid-State Photoelectrochemical Cell with TiO2 Nanotubes Loaded with CdS and CdSe Nanoparticles

Structure and Stability of Pristine and Carboxylate-Covered Anatase TiO2(001) in Aqueous Environment

Contact Info

Product

Resources

About

Structure and reactivity of a water-covered anatase TiO₂(001) surface

Facet-engineered TiO₂ nanomaterials reveal the role of water–oxide interactions in surface protonic conduction

Facet-engineered TiO₂ nanomaterials reveal the role of water–oxide interactions in surface protonic conduction

Water Vapor Photoelectrolysis in a Solid-State Photoelectrochemical Cell with TiO₂ Nanotubes Loaded with CdS and CdSe Nanoparticles

Structure and Stability of Pristine and Carboxylate-Covered Anatase TiO₂(001) in Aqueous Environment