Influence of the electrolytic medium composition on the structural evolution of thin electrochromic molybdenum trioxide films probed by x-ray absorption spectroscopy

Guay, Daniel; Tourillon, G.; Laperrière, Guylaine; Bélanger, Daniel

doi:10.1021/j100198a043

Cited by 14 publications

(5 citation statements)

References 8 publications

(10 reference statements)

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“…8 (for stability purposes the potential scan was restricted to potential positive of 0.1 V) a well-defined cathodic wave is commonly seen when an MoO3 electrode is cycled in a protic electrolyte. 23 In a recent report, MoO3 thin films grown on carbon fiber microelectrodes from a pH 2 (H2SO4) Na2MoO4 solution were characterized by well-defined anodic and cathodic waves and were found to be stable when subjected to continuous potential cycling in dilute sulfuric acid solution.47 Similar results were reported in 1 M 112504 for a film prepared by thermal decomposition of molydenyl acetylacetonate. 48 The presence of a cathodic wave in protic media is related to the faster diffusivity of protons in the MoO3 layer in comparison to lithium cations.…”

Section: Annealing Temperature! Timementioning

confidence: 71%

Electrochromic Behavior of Molybdenum Trioxide Thin Films, Prepared by Thermal Oxidation of Electrodeposited Molybdenum Trisulfide, in Mixtures of Nonaqueous and Aqueous Electrolytes

Laperrière

Lavoie

Bélanger

1996

J. Electrochem. Soc.

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Electrochromic molybdenum trioxide thin films were prepared by thermal oxidation in air of electrodeposited molybdenum trisulfide. MoO, prepared at temperatures ranging from 400 to 550°C were found to be polycrystalline. The best electrochromic properties (coloration efficiency and coloration time) evaluated in 1 M LiClO4/propylene carbonate were observed for films prepared by annealing at 425°C for 10 mm. The coloration efficiency (35 cm'/C) for these optimum films compare well with those reported in the literature. The intensity of coloration of the film (absorbance at 634 nm) was found to scale linearly with film thickness. The electrochemical reduction of MoO, involves the transformation of Mo6 species to Mo', evidenced by x-ray photoelectron spectroscopy. The stability of molybdenum trioxide-coated tin oxide electrodes upon cycling and switching between oxidized and reduced states was investigated by cyclic voltammetry potential-step experiments, and in situ spectroelectrochemistry. The results indicate that the stability of the molybdenum trioxide electrode is improved when it is used in a 0.1 M LiClO4, 14 mM HC104, 2% 11,0/PC solution rather than in a pure, nonaqueous electrolyte such as 0.1 M LiC1O4/PC. The improved stability is related to the fact that the chemical disorder induced by cycling the MoO, electrode in the protic media is much less severe than in the aprotic media, primarily because while Li are intercalated in the latter, only protons are intercalated in the aqueous/nonaqueous mixture.

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Section: Annealing Temperature! Timementioning

confidence: 71%

Electrochromic Behavior of Molybdenum Trioxide Thin Films, Prepared by Thermal Oxidation of Electrodeposited Molybdenum Trisulfide, in Mixtures of Nonaqueous and Aqueous Electrolytes

Laperrière

Lavoie

Bélanger

1996

J. Electrochem. Soc.

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“…AFM observations show that amorphous MoO 3 films are composed of grains ranging from 100 to 190 nm in size, which is made up of smaller particles approximately 25 nm in diameter [129]. MoO 3 film can be prepared by thermal evaporation [6,7,9,18,68,[128][129][130][131][132][133][134][135], flash evaporation [136], rf sputtering [126,127], dc sputtering [137], electron-beam evaporation [138,139], chemical vapor deposition [140][141][142], sol-gel-related techniques [74,143,144], electrodeposition [145,146], thermal decomposition of MoS 3 [147], laser-related deposition [51,52,148], and so forth. Also, different preparation technique often leads to somewhat different properties.…”

Section: Photochromic Behavior and Mechanismmentioning

confidence: 99%

Photochromism in transition-metal oxides

He¹,

Yao²

2004

Res. Chem. Intermed.

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Transition-metal oxides -including tungsten oxide, molybdenum oxide, titanium dioxide, vanadium pentoxide, niobium pentoxide and zinc oxide -exhibit photochromism upon bandgap excitation. These oxides constitute an important group of inorganic chromogenic materials, which is of great significance in the perspective of science and technology. During the past several decades, great progresses have been made in the microstructure, photochromic behavior and mechanism of these oxides, specifically of tungsten oxide. These studies underscore the opportunity of using these materials in photonic applications. The details will be presented in this review.

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“…The intercalation of protons or alkaline metallic ions in the interstices of these oxides occurs as a consequence of charge compensation, 9 generating structural changes 10 and electrochromic effects. [11][12][13] In our previous works, chemical and electrochemical properties of immobilized molybdenum oxides were investigated, especially due to the capacity of these oxides to act as catalyst or mediator in some reactions. The activity of these surfaces toward reductive processes is dependent on structural disorder near the metallic centers, where changes of the Mo oxidation state take place by the intercalation of hydrogen atoms, generating bronzes by the spillover effect.…”

Section: Introductionmentioning

confidence: 99%

“…Aqueous species of Mo(VI) present a complex chemistry as a consequence of various protonation and polymerization equilibria, depending on the experimental conditions, like pH and concentration. , The deposition of molybdenum species on solid surfaces by adsorption from solutions, , chemical vapor deposition (CVD), sol−gel, , or electrochemical techniques produces nonstoichiometric oxides (named as MoO 3 - x ) or bronzes (H x MoO 3 ). The intercalation of protons or alkaline metallic ions in the interstices of these oxides occurs as a consequence of charge compensation, generating structural changes and electrochromic effects. − …”

Section: Introductionmentioning

confidence: 99%

Characterization of Electrochemically Co-deposited Metal−Molybdenum Oxide Films

et al. 2004

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Molybdenum oxide films with and without metal inclusions were electrochemically deposited on glassy carbon electrodes and characterized by soft X-ray spectroscopy, X-ray diffraction, scanning electron microscopy, and Rutherford backscattering spectroscopy. The local coordination of Mo is preferentially octahedral, but changes in the composition promote the appearance of tetrahedral Mo sites. The Mo local structure configurations were evaluated when different potential cycles were used in the modification of the electrode surface. Some metals (Pt, Pd, Rh, and Cu) were co-deposited with the Mo species and their effect on the obtained material was investigated. Pt and Cu favored the formation of bronzes and the enrichment of the film with tetrahedral units of MoO x . The occupancy level of the 4d orbital of Mo was examined as an indicator of interactions between Mo and co-deposited metals.

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Influence of the electrolytic medium composition on the structural evolution of thin electrochromic molybdenum trioxide films probed by x-ray absorption spectroscopy

Cited by 14 publications

References 8 publications

Electrochromic Behavior of Molybdenum Trioxide Thin Films, Prepared by Thermal Oxidation of Electrodeposited Molybdenum Trisulfide, in Mixtures of Nonaqueous and Aqueous Electrolytes

Electrochromic Behavior of Molybdenum Trioxide Thin Films, Prepared by Thermal Oxidation of Electrodeposited Molybdenum Trisulfide, in Mixtures of Nonaqueous and Aqueous Electrolytes

Photochromism in transition-metal oxides

Characterization of Electrochemically Co-deposited Metal−Molybdenum Oxide Films

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