Amorphous titanium hydrogenphosphate—an inorganic sorbent and a catalyst

Ludmány, András; Kurek, Stefan S.; Stokłosa, Andrzej; Wilczyński, Grzegorz M.; Wójtowicz, Anna K.; Zajecki, J.

doi:10.1016/j.apcata.2004.02.035

Cited by 15 publications

(7 citation statements)

References 34 publications

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“…From a practical point of view, this may be beneficial for the overall proton conductivity of ZrHP‐based composite membranes, as amorphous ZrHP exhibits higher conductivity than comparable crystalline and semicrystalline α‐ZrHP and γ‐ZrHP (1–5 × 10 −3 vs. 1.8 × 10 −5 and 2 × 10 −4 S/cm at 100°C and 95%RH, respectively21). Similarly, conductivity of membranes based on amorphous ZrS could potentially benefit from a larger number of surface acid sites exposed, given that amorphous materials generally exhibit larger surface area than crystalline counterparts 28…”

Section: Resultsmentioning

confidence: 99%

Composite proton exchange membranes from zirconium‐based solid acids and PVDF/acrylic polyelectrolyte blends

Zapata

Lee

Meredith

2012

J of Applied Polymer Sci

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Organic-inorganic composite proton exchange membranes (PEMs) are of interest in fuel cell applications because of potential benefits in conductivity, mechanical, and transport properties that may be imparted by the inorganic component. Our previous work showed that polymeric membranes based on blends of poly(vinylidene fluoride) (PVDF) and cross-linked sulfonated acrylic polyelectrolytes (PE) compare favorably against the proton conductivity and mechanical properties of commercial perfluorosulfonic acid-based PEMs. One problem found in the previous study was that crystalline regions in homopolymers of PVDF interfered with the formation of proton conducting pathways by the PE component. In this study, we explore the ability to use proton-conductive zirconiumbased inorganic particles to improve conductivity in such PVDF/PE membranes. Three different particles were considered, namely, zirconium oxide, zirconium hydroxide sulfate, and zirconium hydrogen phosphate. Dispersion of particles in the polymer matrix was limited, resulting in severe aggregation at particle loadings above 5 wt %. Nevertheless, a general improvement in proton conductivity was evidenced in composite membranes with 0.5 to 1 wt % particle loadings. This beneficial effect was particularly noticeable in membranes manufactured from highly crystalline PVDF homopolymers (7 to 14% increase). We propose that the surface of zirconium particles act to provide proton conducting pathways between PE regions that otherwise would become blocked due to PVDF crystallization. In addition to conductivity, composite membranes exhibited enhancement of tensile properties at identical particle loadings, especially in membranes containing more flexible PVDF:HFP copolymers, where a reinforcing stiffening effect was evident (19 to 22% elastic modulus increment).

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Section: Resultsmentioning

confidence: 99%

Composite proton exchange membranes from zirconium‐based solid acids and PVDF/acrylic polyelectrolyte blends

Zapata

Lee

Meredith

2012

J of Applied Polymer Sci

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“…The studies of amorphous TiP ionites remain somewhat isolated and mostly focused on varying the H 3 PO 4 acidity [21][22][23][24]. It is worth noting that there is a lack of comprehensive and methodical studies on the influence of primary synthetic solution composition over properties of isolated TiP ionites for both crystalline and amorphous sorbents.…”

Section: Introductionmentioning

confidence: 99%

Extended study on the synthesis of amorphous titanium phosphates with tailored sorption properties

Маслова¹,

Rusanova²,

Naydenov³

et al. 2012

Journal of Non-Crystalline Solids

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“…Titanium phosphates (TiP) of different compositions are effective ion-exchangers, acid-oxidizers, photocatalysts, solid electrolytes [1][2][3][4][5][6]. Their properties are determined by the Ti/P ratio, crystal and porous structure, morphology and ultimately the synthesis method.…”

Section: Introductionmentioning

confidence: 99%

“…By varying the synthesis conditions of TiP, it is possible to control their main physicochemical properties: specific surface area, crystal and porous structure, and surface acidity. First of all, amorphous and crystalline titanium hydrophosphates Ti(HPO 4 ) 2 have important applications [1][2][3]. The review of TiP preparation methods is presented in papers [1,7,8].…”

Section: Introductionmentioning

confidence: 99%

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Modification of titanium phosphate precipitated from titanylsulfate

Janusz

Khalameida²,

Skwarek

et al. 2018

J Therm Anal Calorim

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The titanium phosphate-synthesized sol-gel method was subjected to the mechanochemical treatment in a planetary ball mill Pulverisette 6 in air or water environment or the hydrothermal treatment at 873 K or 1073 K. The properties of such modified/treated samples were examined using the XRF, XRD, TGA, static light scattering, FTIR Raman and adsorption/ desorption of N 2 methods. The mechanochemical treatment of xerogel samples leads to a small decrease in water contents in the sample, but the structure remains amorphous. Additionally, during milling of the sample aggregation of titanium phosphate particles and a decrease in specific surface area were observed. The hydrothermal treatment of the xerogel sample leads to a crystal product composed of titanium oxide phosphate hydrate, titanium oxide phosphate and titanium dioxide. The TGA analysis confirms the presence of titanium oxide phosphate hydrate. The hydrothermally treated titanium phosphate samples are monodispersed and have a larger specific surface area than the initial sample.

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Amorphous titanium hydrogenphosphate—an inorganic sorbent and a catalyst

Cited by 15 publications

References 34 publications

Composite proton exchange membranes from zirconium‐based solid acids and PVDF/acrylic polyelectrolyte blends

Composite proton exchange membranes from zirconium‐based solid acids and PVDF/acrylic polyelectrolyte blends

Extended study on the synthesis of amorphous titanium phosphates with tailored sorption properties

Modification of titanium phosphate precipitated from titanylsulfate

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