Apparatus for dosing liquid water in ultrahigh vacuum

Balajka, Jan; Pavelec, Jiří; Komora, Mojmír; Schmid, Michael; Diebold, Ulrike

doi:10.1063/1.5046846

Cited by 20 publications

(22 citation statements)

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“…[22] The magnetite surface was exposed to an ultra-pure liquid-water drop in a custom-designed side chamber described in detail elsewhere. [8] A small cryostat ("cold finger") is used for preparing the water drop. Milli-Q water (Milipore, 18.2 MΩ cm) is initially purified by freeze-pump-thaw cycles, and introduced as vapour through a valve into the evacuated side chamber.…”

Section: Methodsmentioning

confidence: 99%

“…[7] Recently, we developed a method to integrate liquid water exposure with a surface science approach. [8] Essentially, UHV-prepared samples are exposed to ultrapure liquid water in a custom-designed cell, without the need for other venting gases (e. g. air, Ar, N 2 ). Before introducing the sample to the cell, water vapour is frozen on a cold finger located above the sample holder, and after sample transfer under UHV conditions, the ice melts and falls onto the UHV-prepared surface.…”

Section: Introductionmentioning

confidence: 99%

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Atomic‐Scale Studies of Fe₃O₄(001) and TiO₂(110) Surfaces Following Immersion in CO₂‐Acidified Water

et al. 2020

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Difficulties associated with the integration of liquids into a UHV environment make surface‐science style studies of mineral dissolution particularly challenging. Recently, we developed a novel experimental setup for the UHV‐compatible dosing of ultrapure liquid water and studied its interaction with TiO2 and Fe3O4 surfaces. Herein, we describe a simple approach to vary the pH through the partial pressure of CO2 (pCO2 ) in the surrounding vacuum chamber and use this to study how these surfaces react to an acidic solution. The TiO2(110) surface is unaffected by the acidic solution, except for a small amount of carbonaceous contamination. The Fe3O4(001)‐(2 ×2 )R45° surface begins to dissolve at a pH 4.0–3.9 (pnormalCO2 =0.8–1 bar) and, although it is significantly roughened, the atomic‐scale structure of the Fe3O4(001) surface layer remains visible in scanning tunneling microscopy (STM) images. X‐ray photoelectron spectroscopy (XPS) reveals that the surface is chemically reduced and contains a significant accumulation of bicarbonate (HCO3−) species. These observations are consistent with Fe(II) being extracted by bicarbonate ions, leading to dissolved iron bicarbonate complexes (Fe(HCO3)2), which precipitate onto the surface when the water evaporates.

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Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Atomic‐Scale Studies of Fe₃O₄(001) and TiO₂(110) Surfaces Following Immersion in CO₂‐Acidified Water

et al. 2020

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“…8,9,21 Over the years, experimental characterizations have moved from ultra-high vacuum condition to solid-liquid interface due to the advancement in surface science techniques. [22][23][24][25][26] As for colloid chemists, the potential distribution at TiO 2 aqueous electrolyte interfaces also interested electrochemists. From the slope of Mott-Schottky plots, the Helmholtz capacitance as a function of pH was determined.…”

mentioning

confidence: 99%

Coupling of Surface Chemistry and Electric Double Layer at TiO₂ Electrochemical Interfaces

Zhang

Hutter

Sprik

2019

J. Phys. Chem. Lett.

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Surfaces of metal oxides at working conditions are usually electrified due to the acidbase chemistry. The charged interface compensated with counterions forms the so-called electric double layer. The coupling of surface chemistry and electric double layer is considered to be crucial but poorly understood because of lacking the information at the atomistic scale. Here, we used the latest development in density functional theory based finitefield molecular dynamics simulation to investigate pH-dependence of the Helmholtz capacitance at electrified rutile TiO 2 (110)-NaCl electrolyte interfaces. It is found that, due to competing forces from surface adsorption and from electric double layer, water molecules have a stronger structural fluctuation at high pH and this leads to a much larger capacitance. It is also seen that, interfacial proton transfers at low pH increase significantly the capacitance value. These findings elucidate the microscopic origin for the same trend observed in titration experiments.Graphical TOC Entry 1 arXiv:1902.00802v3 [cond-mat.soft] 30 Jun 2019The surface chemistry of metal oxides is more involved than that of metals because the surface charge depends on proton exchange driven by pH of the environment. 1,2 The condition in which the surface has no net proton charge is called the point of zero proton charge (PZPC). [3][4][5] However, working conditions for most earth-abundant metal oxide based photocatalysts are not at PZPC and the corresponding solid-liquid interface is highly electrified. 6 By attracting counterions from the solution side, the electric double layer (EDL) is formed at the interface in which the electric field can be as high as 10 9 V/m. 7 Therefore, including the coupling of surface chemistry and EDL at metal oxide-electrolyte interfaces is necessary.The differential capacitance C EDL of the EDL at oxide materials-electrolyte interfaces has been long regarded as a key probe of its structure. For semiconducting oxides, the capacitance can be resolved into three distinct components connected in series: 8,9 The first component is the result of the depletion or accumulation of electrons in the space charge (SC) layer of the semiconductor electrode, which can be 10 to 100 nm thick. The second component C H is the Helmholtz capacitance due to specific adsorption of hydroxide groups or protons and corresponding counter ions. The last component C GC called the Gouy-Chapman capacitance, stems from the diffusive electrolyte and depends on the ionic strength.The relationship between surface structure and ion complexation of oxide-solution interface is a long-standing topic in colloid chemistry. Experimental interest in these metal oxide systems dates back to early 60s. 10,11 In titration experiments, the variation of surface charges due to adsorption/desorption of H + is measured against the pH in solution. To interprete experiments, 2-pK model including a phenomenological neutral site (SOH 0 ), dissociate site (SO − ) and associate site (SOH + 2 ) was introduced ("S" for the su...

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“…• One more advanced technique which has attracted quite an attention recently is a custom-made multi-chamber ultra-high vacuum [46] (UHV) system as shown in Figure 10 for easy sample transport along with additional characterization ability. Its auxiliary system allows these silica samples to transport to the analysis vessel at very low pressure (10− 10 mbar).…”

Section: X-ray Photoelectron Spectroscopy (Xps)mentioning

confidence: 99%

“…Usually, these O-ring caps are best suited for macor rotors. A typical in-situ sample preparation chamber is attached to the UHV system XPS [46]. Advanced Sample Preparation Techniques for Surface Spectroscopy Analysis of Organic… DOI: http://dx.doi.org/10.5772/intechopen.100118…”

Section: Si Solid-state Nmrmentioning

confidence: 99%

Advanced Sample Preparation Techniques for Surface Spectroscopy Analysis of Organic: Inorganic Hybrid Silica Particles

Panigrahi¹,

Mishra²,

Tripathy³

2021

Sample Preparation Techniques for Chemical Analysis

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Silica due to its large inorganic amorphous wall and hydrophilic surface properties renders its suitability for designing different varieties of organic–inorganic silica-based materials. Characterization of such hybrid silica-based materials is one of the fascinating as well as challenging topics to be covered. Surface analysis of these hybrid materials can be done utilizing various techniques, out of which X-ray photoelectron spectroscopy (XPS), 29Si Solid-state Nuclear magnetic resonance (NMR) spectroscopy, and Fourier-transform infrared spectroscopy (FTIR) is the most ideal ones. Thus, before analyzing these silica materials, it requires a massive study on its sample preparation for appropriate characterization of the organic molecules present in the inorganic network. Hence, this chapter will give a brief elucidation of the sample preparation techniques for analyzing the hybrid materials utilizing the above instrumentation techniques.

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Apparatus for dosing liquid water in ultrahigh vacuum

Cited by 20 publications

References 30 publications

Atomic‐Scale Studies of Fe₃O₄(001) and TiO₂(110) Surfaces Following Immersion in CO₂‐Acidified Water

Atomic‐Scale Studies of Fe₃O₄(001) and TiO₂(110) Surfaces Following Immersion in CO₂‐Acidified Water

Coupling of Surface Chemistry and Electric Double Layer at TiO₂ Electrochemical Interfaces

Advanced Sample Preparation Techniques for Surface Spectroscopy Analysis of Organic: Inorganic Hybrid Silica Particles

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Apparatus for dosing liquid water in ultrahigh vacuum

Cited by 20 publications

References 30 publications

Atomic‐Scale Studies of Fe3O4(001) and TiO2(110) Surfaces Following Immersion in CO2‐Acidified Water

Atomic‐Scale Studies of Fe3O4(001) and TiO2(110) Surfaces Following Immersion in CO2‐Acidified Water

Coupling of Surface Chemistry and Electric Double Layer at TiO2 Electrochemical Interfaces

Advanced Sample Preparation Techniques for Surface Spectroscopy Analysis of Organic: Inorganic Hybrid Silica Particles

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Product

Resources

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Atomic‐Scale Studies of Fe₃O₄(001) and TiO₂(110) Surfaces Following Immersion in CO₂‐Acidified Water

Atomic‐Scale Studies of Fe₃O₄(001) and TiO₂(110) Surfaces Following Immersion in CO₂‐Acidified Water

Coupling of Surface Chemistry and Electric Double Layer at TiO₂ Electrochemical Interfaces