Sol–gel synthesis of macroporous barium zirconate monoliths from ionic precursors via a phase separation route

Guo, Xingzhong; Wang, Zichen; Song, Jie Guang; Ye, Hui

doi:10.1016/j.jpcs.2016.11.012

Cited by 11 publications

(12 citation statements)

References 29 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The associated BET surface area values also follow the nonmonotonic variation of mesopore and porosity with largest surface area for powder with highest porosity and least surface area for powder of lowest porosity (Table 1). This observation is in agreement with the fact that mesopores having direct links with the sample's BET surface area and control the BET surface area 2,41 …”

Section: Resultssupporting

confidence: 88%

Variation of citrate to metal cation ratio for dense and phase pure BaZrO₃ via autocombustion synthesis

Manju

Babu

et al. 2022

J Am Ceram Soc.

View full text Add to dashboard Cite

In this work, we demonstrate how the metal–citrate complex structure formed in the gel reflects the true stoichiometry of the redox mixtures to yield a highly dense BaZrO3 ceramic obtained as a combustion product in the sol‐gel autocombustion technique. By systematically varying the citric acid to metal cation ratio (C/M) between 0.56, 1.0, 1.5, and 2, we show that the optimal synthesis parameters correspond to C/M ratio of 1.5, at which ratio complete chelation of citrates happen with nitrates. This was confirmed using TGA, which showed a single‐step weight loss peak corresponding to C/M =1.5 but multiple peaks in C/M ratios of 0.56 and 1. PXRD and FTIR measurements on all the burnt powders showed multiphase peaks for the C/M ratios 0.56 and 1 but only peaks corresponding to BaZrO3 for C/M = 1.5, apart from a very tiny BaCO3$_3$ peak. Combustion behavior of each sol‐gel corresponding to C/M ratios 0.56, 1.0, 1.5, and 2.0 is described in detail, wherein 0.56 and 1.0 sol‐gels were found to belong to the smouldering/less intense flame‐type combustion, while 1.5 and 2 belonged to the intense flame combustion, contradicting oxidant to reductant ratio (O/R) calculations that require a stoichiometric combustion for C/M ratio of 0.56 to result in an intense flame combustion. This discrepancy was explained by the optimal usage of NO3−$_3^-$ ions in the gel structure corresponding to C/M ratio of 1.5 since a complete chelation of citrates to nitrates ions happen for C/M = 1.5. The observed combustion behavior, phase purity, and other characteristics of stoichiometric/ nonstoichiometric combustion products are illustrated by means of the extent of the 3D metal–citrate complex network formed as a function of C/M. The density of the sintered pellets that were sintered at a temperature of 1650∘$^\circ$C was found to be the best at 99.6%$\%$ for the C/M ratio 1.5. This is the highest ever reported density for BaZrO3 ceramic demonstrating that C/M ratio of 1.5 represents that metal to cation ratio for which best chelation of citrates happen with nitrates resulting in the formation of dense BaZrO3 ceramics. A comparison of BaZrO3$_3$ pellet made by solid‐state synthesis technique yielded a low value of density of 97.5%$\%$. Impedance spectroscopy measurements done on all BaZrO3$_3$ pellets yielded the lowest grain‐boundary resistance for the pellet made by the sol‐gel technique with C/M ratio of 1.5.

show abstract

Section: Resultssupporting

confidence: 88%

Variation of citrate to metal cation ratio for dense and phase pure BaZrO₃ via autocombustion synthesis

Manju

Babu

et al. 2022

J Am Ceram Soc.

View full text Add to dashboard Cite

show abstract

“…In 2016 and 2017, the same authors extended this method to produce yttria-stabilized zirconia (YZA) and barium zirconate, obtaining xerogels with high porosity and surface area [ 79 , 80 ]. In this case, formamide was also added as a gelation agent.…”

Section: Macroporous Non-siliceous Single Oxide Multi-oxide and Non-oxide Monolithsmentioning

confidence: 99%

“…This is contrary to what is observed in reference [ 78 ], where no EG is used. The sol-gel/phase separation process is schematically represented at [ 80 ]. Optimized amounts of PEO and PO were found at 0.1 g and 0.36 mL, respectively, and it should be stressed that TMOS or TEOS were employed for solvent exchange.…”

Section: Macroporous Non-siliceous Single Oxide Multi-oxide and Non-oxide Monolithsmentioning

confidence: 99%

“…When less reactive ionic precursors (metal salts) are used, synthesis strategies involve, most of the times, an epoxide-mediated method, combined with polymerizationinduced spinodal decomposition, as shown in Figure 16, where two of the most representative synthesis schemes are displayed. Macroporous oxide monoliths of compositions Al2O3, TiO2, ZrO2, Cr2O3, MgO, and Fe2O3, among others, have been successfully prepared by these approaches [72,76,78,[81][82][83], as well as zirconates [80,84], spinels [85][86][87][88], titanates [89], etc. When less reactive ionic precursors (metal salts) are used, synthesis strategies involve, most of the times, an epoxide-mediated method, combined with polymerization-induced spinodal decomposition, as shown in Figure 16, where two of the most representative synthesis schemes are displayed.…”

Section: Other Non-siliceous Macroporous Monolithic Systemsmentioning

confidence: 99%

“…When less reactive ionic precursors (metal salts) are used, synthesis strategies involve, most of the times, an epoxide-mediated method, combined with polymerization-induced spinodal decomposition, as shown in Figure 16, where two of the most representative synthesis schemes are displayed. Macroporous oxide monoliths of compositions Al 2 O 3 , TiO 2 , ZrO 2 , Cr 2 O 3 , MgO, and Fe 2 O 3 , among others, have been successfully prepared by these approaches [72,76,78,[81][82][83], as well as zirconates [80,84], spinels [85][86][87][88], titanates [89], etc.…”

Section: Other Non-siliceous Macroporous Monolithic Systemsmentioning

confidence: 99%

See 2 more Smart Citations

Macroporosity Control by Phase Separation in Sol-Gel Derived Monoliths and Microspheres

Marques

Vale

2021

Materials

View full text Add to dashboard Cite

Macroporous and hierarchically macro/mesoporous materials (mostly monoliths and microspheres) have attracted much attention for a variety of applications, such as supporting or enabling materials in chromatography, energy storage and conversion, catalysis, biomedical devices, drug delivery systems, and environmental remediation. A well-succeeded method to obtain these tailored porous materials relies on the sol-gel technique, combined with phase separation by spinodal decomposition, and involves as well emulsification as a soft template, in the case of the synthesis of porous microspheres. Significant advancements have been witnessed, in terms of synthesis methodologies optimized either for the use of alkoxides or metal–salts and material design, including the grafting or immobilization of a specific species (or nanoparticles) to enable the most recent trends in technological applications, such as photocatalysis. In this context, the evolution, in terms of material composition and synthesis strategies, is discussed in a concerted fashion in this review, with the goal of inspiring new improvements and breakthroughs in the framework of porous materials.

show abstract

Optimizing barium promoter for nickel catalyst supported on yttria‐stabilized zirconia in dry reforming of methane

Al‐Fatesh

Ibrahim

Osman

et al. 2023

Energy Science & Engineering

View full text Add to dashboard Cite

Barium doping effect on the activity and stability of nickel-based catalysts, supported on yttria-stabilized zirconia (Ni-YZr), was investigated in dry reforming of methane. Catalysts were characterized by several techniques (nitrogen sorption, X-ray diffraction [XRD], scanning electron microscopy with energy dispersive X-ray, transmission electron microscopy [TEM], thermogravimetric analysis [TGA], temperature programmed oxidation, CO 2 -TPD, H 2 -TPR) and were tested in a fixed-bed reactor at 800°C and 42,000 mL/h g cat . Barium played a crucial role in enhancing catalyst reducibility and CO 2 adsorption at high temperatures, as indicated by the activity and stability of the Ni-YZr catalyst. The addition of 4.0 wt% of barium appeared to be the optimal loading, allowing for CH 4 conversion of 82%, which remained constant for 7 h of reaction, compared with 72% of bariumunpromoted Ni-YZr at 800°C. TEM images of the spent catalysts revealed the formation of multiwalled carbon nanotubes on all samples. The TGA analysis showed, however, that an increase in baria loading significantly reduced the coke formation amount, indicating the inhibition of coke formation and the enhancement of the catalytic activity. Such improvement in activity and stability was attributed to the incorporation of barium into

show abstract

Sol–gel synthesis of macroporous barium zirconate monoliths from ionic precursors via a phase separation route

Cited by 11 publications

References 29 publications

Variation of citrate to metal cation ratio for dense and phase pure BaZrO₃ via autocombustion synthesis

Variation of citrate to metal cation ratio for dense and phase pure BaZrO₃ via autocombustion synthesis

Macroporosity Control by Phase Separation in Sol-Gel Derived Monoliths and Microspheres

Optimizing barium promoter for nickel catalyst supported on yttria‐stabilized zirconia in dry reforming of methane

Contact Info

Product

Resources

About

Sol–gel synthesis of macroporous barium zirconate monoliths from ionic precursors via a phase separation route

Cited by 11 publications

References 29 publications

Variation of citrate to metal cation ratio for dense and phase pure BaZrO3 via autocombustion synthesis

Variation of citrate to metal cation ratio for dense and phase pure BaZrO3 via autocombustion synthesis

Macroporosity Control by Phase Separation in Sol-Gel Derived Monoliths and Microspheres

Optimizing barium promoter for nickel catalyst supported on yttria‐stabilized zirconia in dry reforming of methane

Contact Info

Product

Resources

About

Variation of citrate to metal cation ratio for dense and phase pure BaZrO₃ via autocombustion synthesis

Variation of citrate to metal cation ratio for dense and phase pure BaZrO₃ via autocombustion synthesis