A2Zr2O7 (A = Nd, Sm, Gd, Yb) zirconate ceramics with pyrochlore-type structure for high-temperature negative temperature coefficient thermistor

Wang, Yige; Gao, Bo; Wang, Qian; Li, Xiaohui; Su, Zhi; Chang, Aimin

doi:10.1007/s10853-020-05104-5

Cited by 29 publications

(3 citation statements)

References 33 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…For the Er 2 Zr 2 O 7 sample, the thermal conducti- vity goes from nearly 1.2 W/mK at 300 K to 0.8 W/mK at 773 K. For the remaining samples, lower values of the thermal conductivity are obtained. Similar results were reported by Jie and collaborators [23], where the decrease in temperature of the thermal conductivity could be associated with the improvement in the efficiency of the thermal barrier coating compounds [23,[24][25][26][27][28][29][30][31][32][33][34][35][36][37][38][39][40][41][42]. Figure 7b) shows the values of the thermal conductivity extracted from Fig.…”

Section: Thermolectric Propertiessupporting

confidence: 83%

Electrical and thermal conductivities of rare-earth A2Zr2O7 (A = Pr, Nd, Sm, Gd, and Er)

et al. 2021

View full text Add to dashboard Cite

Structural and thermoelectric properties of rare-earth zirconates A2Zr2O7, with A = Pr, Nd, Sm, Gd, and Er, were studied. Samples were prepared by solid-state reaction at ambient pressure with temperatures between 1000 and 1400 °C. The resulting compounds were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM/EDS). The XRD analyses showed the formation of polycrystalline Pr2Zr2O7, Nd2Zr2O7, Sm2Zr2O7, Gd2Zr2O7 and Er2Zr2O7 phases, with a cubic cell (space group Fm3m) and traces of the raw used materials. The micrographs obtained by SEM show the formation of heterogeneous grains with a size that ranges from 0.7 to 4.7 μm. All A2Zr2O7 samples present porous surfaces. Thermal conductivities were measured at different temperatures, from 300 to 900 K. In most of the samples, the thermal conductivity monotonically decreases with temperature, from 0.40 – 1.17 W/mK at 300 K to 0.27 – 0.77 W/mK at 773.15 K. At a fixed temperature, the thermal conductivity decreases almost monotonically with the ionic radius (IR) of the rare-earth elements (where IR (Er3+) = 0.890 Å < IR (Gd3+) = 0.938 Å < IR (Sm3+) = 0.958 Å < IR (Nd3+) = 0.983 Å < IR (Pr3+) = 0.99 Å).

show abstract

Section: Thermolectric Propertiessupporting

confidence: 83%

Electrical and thermal conductivities of rare-earth A2Zr2O7 (A = Pr, Nd, Sm, Gd, and Er)

et al. 2021

View full text Add to dashboard Cite

show abstract

“…Therefore, rare earth elements have received more and more attention in the modification of photocatalysts [17][18][19][20]. Although it has been reported in the literature that rare earth-doped Sm 2 Zr 2 O 7 has been prepared by the stearic acid method, and it has been found that rare earth-doped ions can promote photocatalytic performance [21,22], the preparation process for Sm 2 Zr 2 O 7 requires hightemperature sintering (900 • C) and long reaction times. Additionally, the mechanism by which rare earth ion doping promotes photocatalytic activity is not very clear.…”

Section: Introductionmentioning

confidence: 99%

La-Doped Sm2Zr2O7/PU-Coated Leather Composites with Enhanced Mechanical Properties and Highly Efficient Photocatalytic Performance

Chen,

Li,

Hou

et al. 2024

Materials

View full text Add to dashboard Cite

Flexible La-doped Sm2Zr2O7/polyurethane (PU) coated leather composites were synthesized using a one-step hydrothermal method, with highly efficient photocatalytic degradation properties by coating the La-doped Sm2Zr2O7/PU emulsion onto the leather and drying it. The phase composition and optical properties of the as-prepared photocatalytic material were systematically characterized. The result revealed that La was doped in Sm2Zr2O7 successfully, and the prepared samples still possessed pyrochlore structure. The absorption edge of the prepared samples exhibited a red-shift with the increase in La doping, indicating that La doping could broaden the absorbance range of the La-doped Sm2Zr2O7 materials. The catalytic performance of La-doped Sm2Zr2O7/PU composite emulsion coating on the photocatalytic performance of leather was studied with Congo red solution as the target pollutant. The results showed that the best photocatalytic property was found in the 5% La-doped Sm2Zr2O7 nanomaterial at a concentration of 3 g/L. The resulting 5% La-doped Sm2Zr2O7 nanomaterial exhibited a high specific surface area of 73.5 m2/g. After 40 min of irradiation by a 450 W xenon lamp, the degradation rate of Congo red reached 93%. Moreover, after surface coating, the La-doped Sm2Zr2O7/PU coated leather composites showed obviously improved mechanical properties, as the tensile strength of La-doped Sm2Zr2O7/PU coated leather composites increased from 6.3 to 8.4 MPa. The as-prepared La-doped Sm2Zr2O7/PU coated leather composites with enhanced mechanical properties and highly efficient photocatalytic performance hold promising applications in the treatment of indoor volatile organic compounds.

show abstract

“…Pr 2 Zr 2 O 7 with a pyrochlore structure is a promising candidate for the quantum spin ices [10,32]. Yb 2 Zr 2 O 7 (γ = 1.368) can have both a defect fluorite structure [33] and a δ-phase (rhombohedral, sp. gr.…”

Section: Introductionmentioning

confidence: 99%

Influence of Synthesis Conditions on the Crystal, Local Atomic, Electronic Structure, and Catalytic Properties of (Pr1−xYbx)2Zr2O7 (0 ≤ x ≤ 1) Powders

Popov,

Markova,

Zubavichus

et al. 2023

Crystals

View full text Add to dashboard Cite

The influence of Yb3+ cations substitution for Pr3+ on the structure and catalytic activity of (Pr1−xYbx)2Zr2O7 powders synthesized via coprecipitation followed by calcination is studied using a combination of long- (s-XRD), medium- (Raman, FT-IR, and SEM-EDS) and short-range (XAFS) sensitive methods, as well as adsorption and catalytic techniques. It is established that chemical composition and calcination temperature are the two major factors that govern the phase composition, crystallographic, and local-structure parameters of these polycrystalline materials. The crystallographic and local-structure parameters of (Pr1−xYbx)2Zr2O7 samples prepared at 1400 °C/3 h demonstrate a tight correlation with their catalytic activity towards propane cracking. The progressive replacement of Pr3+ with Yb3+ cations gives rise to an increase in the catalytic activity. A mechanism of the catalytic cracking of propane is proposed, which considers the geometrical match between the metal–oxygen (Pr–O, Yb–O, and Zr–O) bond lengths within the active sites and the size of adsorbed propane molecule to be the decisive factor governing the reaction route.

show abstract

A2Zr2O7 (A = Nd, Sm, Gd, Yb) zirconate ceramics with pyrochlore-type structure for high-temperature negative temperature coefficient thermistor

Cited by 29 publications

References 33 publications

Electrical and thermal conductivities of rare-earth A2Zr2O7 (A = Pr, Nd, Sm, Gd, and Er)

Electrical and thermal conductivities of rare-earth A2Zr2O7 (A = Pr, Nd, Sm, Gd, and Er)

La-Doped Sm2Zr2O7/PU-Coated Leather Composites with Enhanced Mechanical Properties and Highly Efficient Photocatalytic Performance

Influence of Synthesis Conditions on the Crystal, Local Atomic, Electronic Structure, and Catalytic Properties of (Pr1−xYbx)2Zr2O7 (0 ≤ x ≤ 1) Powders

Contact Info

Product

Resources

About