Interstitial oxide ion migration in scheelite-type electrolytes: a combined neutron diffraction and computational study

Ferrara, Chiara; Mancini, Alessandro; Ritter, C.; Malavasi, Lorenzo; Tealdi, Cristina

doi:10.1039/c5ta06575e

Cited by 25 publications

(29 citation statements)

References 56 publications

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“…For example, when trivalent La 3+ ions are partly substituted for Pb 2+ site of PbWO 4 , oxide ion interstitials are created as Pb 1-x La x WO 4+x/2 to exhibit a high oxide ion conduction at elevated temperature. [3][4][5] Similar enhancement in ionic conduction due to the oxide ion interstitials has been reported for other scheelite-type structured systems, such as PbMoO 4 , 6 CaMoO 4 , 7 BaMoO 4 , 8 high-temperature form of CeNbO 4 , 9 LaNbO 4 , 10,11 or GdNbO 4 . 12 However, CaWO 4 with mineral name of scheelite is unlikely to form solid solution by lanthanum substitution incorporating excess oxide ions at interstitial site.…”

Section: Accepted M Msupporting

confidence: 65%

Electrochemical Properties of Cs and La Co-doped CaWO<sub>4</sub> Oxide Ion Conductor

et al. 2022

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To clarify the contribution of defect structure of CaWO4-based system on the oxide ion conduction properties, we doped both cesium and lanthanum ions into CaWO 4 as Ca 0.9 Cs x La 0.1-x WO 4.05-x . Scheelite-type structured solid solution can be obtained for the Cs-rich region (x ≥ 0.05) with oxygen deficiency, while second phase appears for La-rich region (x ≤ 0.025) assuming excess oxide ions. In the present system, a bend in Arrhenius plot of conductivity is observed around 850 °C as the typical CaWO 4 -based system even co-doping with La ions. In terms of the compositional dependence, ionic conduction develops from x = 0.05 with the amount of cation vacancy below 800 °C, while the conductivity enhancement starts at the La-rich region above 900 °C. This indicates that not only oxide ion vacancy but also interstitial attribute to the oxide ion conduction at high-temperature, which is also suggested by the activation energy.

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Section: Accepted M Msupporting

confidence: 65%

Electrochemical Properties of Cs and La Co-doped CaWO<sub>4</sub> Oxide Ion Conductor

et al. 2022

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“…7,21 The fergusonitescheelite transition temperature is decreased by W 6+ doping, with the x ¼ 0.16 sample appearing almost tetragonal at room temperature. 23 The presence of interstitial oxide ions in LNWO also leads to modulated ordering schemes 24,25 similar to those observed in Ce 4+ -doped CeNbO 4+d . 26 Oxide ion mobility is facilitated in LNWO via an interstitialcy mechanism that probably incorporates both interstitialframework and interstitial-interstitial jumps.…”

Section: Introductionmentioning

confidence: 57%

Exploring the nature of the fergusonite–scheelite phase transition and ionic conductivity enhancement by Mo⁶⁺doping in LaNbO₄

et al. 2021

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“…Thus, for the functionality of the given nano-SrMoO 4 sensing material used at high temperature, oxygen diffusion from lattice and interstitial sites are required for the redox reaction. It is known that scheelite oxides have the ability to include high concentrations of stable interstitial oxygen ions within its structure, and previous research has shown that this leads to a compensating mechanism to enhance structural stability under low oxygen partial pressure environments at high temperature [78][79][80][81][82].…”

Section: So 2 Sensor Testing Of the Nano-srmoo 4 And Post-mortem Analmentioning

confidence: 99%

Molybdenum and tungsten oxide based gas sensors for high temperature detection of environmentally hazardous sulfur species

Çiftyürek

Sabolsky

2016

Sensors and Actuators B: Chemical

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a b s t r a c tThere is an increasing desire to control and monitor gas emissions from coal-fired power plants and other industrial systems. With this desire, there is a growing need for distributed gas sensors to monitor these emissions at high temperature ( > 600 • C), especially for pollutants such as SO 2 and H 2 S. The objective of this work was to investigate molybdenum and tungsten binary and ternary oxide thick films on a chemiresistive sensor platform for monitoring of gas sulfur species. The work evaluated the SO 2 sensitivity of WO 3 , MoO 3 , SrMoO 4 , NiMoO 4 , Sr 2 MgMoO 6-␦ (SMM), Sr 2 MgWO 6-␦ (SMW), NiWO 4 , and SrWO 4 compositions at 600-1000 • C. The SrMoO 4 composition at both the micro-and nano-particulate scale showed the most promise in sensitivity, stability and selectivity to SO 2 up to 1000 • C. Hydrothermallysynthesized nano-SrMoO 4 showed the highest sensor response with the R max values of −17.2, −50.2 and −40.5 upon exposure to a 20 min pulse of 2000 ppm of SO 2 at 600 • C, 800 • C and 1000 • C, respectively. Similar sensitivity trends were distinguished down to 1-5 min SO 2 pulses. The nano-SrMoO 4 showed low cross-selectivity to H 2 and CO. Finally, the nano-SrMoO 4 sensor was also tested with H 2 and coal syngas containing 5-100 ppm H 2 S, where high sensitivities were realized for both, but the sensing mechanism was altered in the latter (n-type to p-type semiconducting behavior). In order to better understand the sensing mechanism, extensive microstructural, electronic and chemical property characterizations were completed in this work.

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Interstitial oxide ion migration in scheelite-type electrolytes: a combined neutron diffraction and computational study

Abstract: W-doped LnNbO4+d compounds (Ln = La, Nd) have been recently proposed as novel interstitial-based oxide ion conductors.

Cited by 25 publications

References 56 publications

Electrochemical Properties of Cs and La Co-doped CaWO<sub>4</sub> Oxide Ion Conductor

Electrochemical Properties of Cs and La Co-doped CaWO<sub>4</sub> Oxide Ion Conductor

Exploring the nature of the fergusonite–scheelite phase transition and ionic conductivity enhancement by Mo⁶⁺doping in LaNbO₄

Molybdenum and tungsten oxide based gas sensors for high temperature detection of environmentally hazardous sulfur species

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Interstitial oxide ion migration in scheelite-type electrolytes: a combined neutron diffraction and computational study

Abstract: W-doped LnNbO4+d compounds (Ln = La, Nd) have been recently proposed as novel interstitial-based oxide ion conductors.

Cited by 25 publications

References 56 publications

Electrochemical Properties of Cs and La Co-doped CaWO<sub>4</sub> Oxide Ion Conductor

Electrochemical Properties of Cs and La Co-doped CaWO<sub>4</sub> Oxide Ion Conductor

Exploring the nature of the fergusonite–scheelite phase transition and ionic conductivity enhancement by Mo6+doping in LaNbO4

Molybdenum and tungsten oxide based gas sensors for high temperature detection of environmentally hazardous sulfur species

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Exploring the nature of the fergusonite–scheelite phase transition and ionic conductivity enhancement by Mo⁶⁺doping in LaNbO₄