Hierarchically structured, oxygen deficient, tungsten oxide morphologies for enhanced photoelectrochemical charge transfer and stability

Chen, P.; Baldwin, M.J.; Bandaru, Prabhakar R.

doi:10.1039/c7ta04118g

Cited by 40 publications

(17 citation statements)

References 55 publications

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“…This could somehow accommodate the reason why BCW internal charge transfer could be pushed thorough so far, but irreversibly. It does not share such features as CCWO, has fewer defects from spontaneous, chaotic, anisotropic pairing, and internal B-site ions are also less polarized; i.e., the PL-inactive Ce 4+ /W 4+ pair has Δ Z = 0 in comparison to emitting Ce 3+ /W 5+ Δ Z = 1. − This subject will be divulged further in the upcoming optical paper concerning dopants and encountered luminescence issues.…”

Section: Resultsmentioning

confidence: 99%

“…This makes the BCW case even more anomalous. Since interstitial oxygen-bound defects can cause such effects − we assume that Ba 2 PrWO 6 could behave the same way…”

Section: Resultsmentioning

confidence: 99%

“…The PL photobleaching phenomenon was noticed solely in BCW during NUV PL measurements. Its origin is not fully understood yet, but connection to some kind of internal (probably interstitial) oxygen evolution and irreversible charge transfer within a relatively small unit cell has been noted using EPR and XPS. ,− …”

Section: Discussionmentioning

confidence: 99%

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Synthesis Attempt and Structural Studies of Novel A₂CeWO₆ Double Perovskites (A²⁺ = Ba, Ca) in and outside of Ambient Conditions

et al. 2022

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This comprehensive work showcases two novel, rock-salt-type minerals in the form of amphoteric cerium–tungstate double perovskite and ilmenite powders created via a high-temperature solid-state reaction in inert gases. The presented studies have fundamental meaning and will mainly focus on a detailed synthesis description of undoped structures, researching their possible polymorphism in various conditions and hinting at some nontrivial physicochemical properties like charge transfer for upcoming optical studies after eventual doping with selectively chosen rare-earth ions. The formerly mentioned, targeted A 2 BB′X 6 group of compounds contains mainly divalent alkali cations in the form of XII A = Ba 2+ , Ca 2+ sharing, here, oxygen-arranged clusters ( II X = O 2– ) with purposely selected central ions from f-block VI B = Ce 4/3+ and d-block VI B′ = W 4/5/6+ since together they often possess some exotic properties that could be tuned and implemented into futuristic equipment like sensors or energy converters. Techniques like powder XRD, XPS, XAS, EPR, Raman, and FTIR spectroscopies alongside DSC and TG were involved with an intent to thoroughly describe any possible changes within these materials. Mainly, to have a full prospect of any desirable or undesirable phenomena before diving into more complicated subjects like: energy or charge transfer in low temperatures; to reveal whether or not the huge angular tilting generates large enough dislocations within the material’s unit cell to change its initial properties; or if temperature and pressure stimuli are responsible for any phase transitions and eventual, irreversible decomposition.

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Section: Resultsmentioning

confidence: 99%

“…This makes the BCW case even more anomalous. Since interstitial oxygen-bound defects can cause such effects − we assume that Ba 2 PrWO 6 could behave the same way…”

Section: Resultsmentioning

confidence: 99%

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Synthesis Attempt and Structural Studies of Novel A₂CeWO₆ Double Perovskites (A²⁺ = Ba, Ca) in and outside of Ambient Conditions

et al. 2022

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“…Tungsten trioxide (WO 3 ) is a well-known material studied for many years for its applications in gas sensing [1,2], electrochromism [3,4,5,6], photochromism [7,8,9,10], and photocatalysis [11,12]. It was recently shown [13] that oxygen sub-stoichiometry in tungsten oxide (with WO 3-x chemical composition) can have a strong impact on the optical properties on its optical properties.…”

Section: Introductionmentioning

confidence: 99%

Nanoparticles (NPs) of WO3-x Compounds by Polyol Route with Enhanced Photochromic Properties

et al. 2019

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Tungsten trioxide (WO3) is well-known as one of the most promising chromogenic compounds. It has a drastic change of coloration induced from different external stimuli and so its applications are developed as gas sensors, electrochromic panels or photochromic sensors. This paper focuses on the photochromic properties of nanoWO3, with tunable composition (with tunable oxygen sub-stoichiometry). Three reference samples with yellow, blue and black colors were prepared from polyol synthesis followed by post annealing under air, none post-annealing treatment, or a post-annealing under argon atmosphere. These three samples differ in terms of crystallographic structure (cubic system versus monoclinic system), oxygen vacancy concentration, electronic band diagram with occurrence of free or trapped electrons and their photochromic behavior. Constituting one main finding, it is shown that the photochromic behavior is highly dependent on the compound’s composition/color. Rapid and important change of coloration under UV (ultraviolet) irradiation was evidenced especially on the blue compound, i.e., the photochromic coloring efficiency of this compound in terms of contrast between bleached and colored phase, as the kinetic aspect is high. The photochromism is reversible in a few hours. This hence opens a new window for the use of tungsten oxide as smart photochromic compounds.

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“…[ 24 ] The third doublet at 33.4 and 34.6 eV is due to W 4+ . [ 25 ] The observed peak positions of the second and third feature are slightly above the expectation for pure oxide compounds of this oxidation state and it can be speculated that this slight shift of the BE could originate from some Cl − coordination process in the lattice. Tungsten oxychlorides with W oxidation states lower than +III (i.e., WOCl 4 3− ) are unstable in chloride ion‐rich electrolytes and tend to be converted to tungsten chlorides.…”

Section: Resultsmentioning

confidence: 77%

Tungsten Oxytetrachloride as a Positive Electrode for Chloride‐Ion Batteries

et al. 2022

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the cationic shuttle of Na þ , K þ , Mg 2þ , Ca 2þ , and Zn 2þ ions and anionic shuttle based on F À and Cl À ion. [3] One promising alternative to LIBs is rechargeable chlorideion batteries (CIBs) [4] which offer high theoretical volumetric energy densities up to 2500 Wh L À1 , comparable with lithiumsulfur batteries. [5] Energy storage based on chloride-ion transfer would be favorable due to the lower cost and higher abundance of chlorides as compared with lithium. [6] The first proof of concept of a CIB was demonstrated by Zhao et al., with CoCl 2 , VCl 3 , and BiCl 3 cathodes, which suffered from rapid capacity fading during cycling attributed to the high volume changes due to the underlying conversion-based storage mechanism and solubility issues of cathodes in the electrolyte. [7] Layered double hydroxides, which are less prone to dissolve in the electrolyte, could demonstrate a cyclability of CIBs beyond 1000 cycles. [8] Recently, chlorideion-intercalated graphite was used as a cathode in combination with aqueous electrolytes and demonstrated the feasibility of a high cycle life with over 4000 cycles. [9] Furthermore, progress has also been shown in the development of inorganic chloride-ion-conducting solid electrolyte CsSnCl 3 with a large electrochemical stability window of 6.1 V and a room temperature conductivity of %10 À4 S cm À1 . [5d,10] In general, the field of CIB holds great promise for the exploration of novel electrode materials. Mixed-anion transition metal-based oxychloride materials are potential candidates for electrodes, that can offer better structural stability and facilitate solvent processing as compared with their chloride analogues. The layered VOCl cathode investigated by Gao et al. demonstrated stable cycling performance with a reversible capacity of 113 mAh g À1 after 100 cycles. [5a] Other examples like FeOCl [11] and BiOCl [3g] could be used as cathode material for CIBs and exhibited moderate electrochemical performances. Both VOCl and FeOCl have an orthorhombic structure, with a layered arrangement of chloride and oxygen atoms, while Fe 3þ /V 3þ is incorporated at the center of the polyhedron. In contrast, BiOCl has a tetragonal structure, where chloride ions lie between the Bi and O bilayers. In this report, we evaluate the electrochemical performance of tetragonal-structured tungsten oxytetrachloride (WOCl 4 ) as an electrode material for CIBs (theoretical

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Hierarchically structured, oxygen deficient, tungsten oxide morphologies for enhanced photoelectrochemical charge transfer and stability

Abstract: The role of non-stoichiometry in hierarchically structured tungsten oxide compounds for enhancing the photoelectrochemical response and stability.

Cited by 40 publications

References 55 publications

Synthesis Attempt and Structural Studies of Novel A₂CeWO₆ Double Perovskites (A²⁺ = Ba, Ca) in and outside of Ambient Conditions

Synthesis Attempt and Structural Studies of Novel A₂CeWO₆ Double Perovskites (A²⁺ = Ba, Ca) in and outside of Ambient Conditions

Nanoparticles (NPs) of WO3-x Compounds by Polyol Route with Enhanced Photochromic Properties

Tungsten Oxytetrachloride as a Positive Electrode for Chloride‐Ion Batteries

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Hierarchically structured, oxygen deficient, tungsten oxide morphologies for enhanced photoelectrochemical charge transfer and stability

Abstract: The role of non-stoichiometry in hierarchically structured tungsten oxide compounds for enhancing the photoelectrochemical response and stability.

Cited by 40 publications

References 55 publications

Synthesis Attempt and Structural Studies of Novel A2CeWO6 Double Perovskites (A2+ = Ba, Ca) in and outside of Ambient Conditions

Synthesis Attempt and Structural Studies of Novel A2CeWO6 Double Perovskites (A2+ = Ba, Ca) in and outside of Ambient Conditions

Nanoparticles (NPs) of WO3-x Compounds by Polyol Route with Enhanced Photochromic Properties

Tungsten Oxytetrachloride as a Positive Electrode for Chloride‐Ion Batteries

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Synthesis Attempt and Structural Studies of Novel A₂CeWO₆ Double Perovskites (A²⁺ = Ba, Ca) in and outside of Ambient Conditions

Synthesis Attempt and Structural Studies of Novel A₂CeWO₆ Double Perovskites (A²⁺ = Ba, Ca) in and outside of Ambient Conditions