The Effect of Sulfated Zirconia and Zirconium Phosphate Nanocomposite Membranes on Fuel-Cell Efficiency

To investigate the effect of acidic nanoparticles on proton conductivity, permeability, and fuel-cell performance, a commercial Nafion^® 117 membrane was impregnated with zirconium phosphates (ZrP) and sulfated zirconium (S-ZrO₂) nanoparticles. As they are more stable than other solid superacids, sulfated metal oxides have been the subject of intensive research. Meanwhile, hydrophilic, proton-conducting inorganic acids such as zirconium phosphate (ZrP) have been used to modify the Nafion^® membrane due to their hydrophilic nature, proton-conducting material, very low toxicity, low cost, and stability in a hydrogen/oxygen atmosphere. A tensile test, water uptake, methanol crossover, Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), thermal gravimetric analysis (TGA), and scanning electron microscopy (SEM) were used to assess the capacity of nanocomposite membranes to function in a fuel cell. The modified Nafion^® membrane had a higher water uptake and a lower water content angle than the commercial Nafion^® 117 membrane, indicating that it has a greater impact on conductivity. Under strain rates of 40, 30, and 20 mm/min, the nanocomposite membranes demonstrated more stable thermal deterioration and higher mechanical strength, which offers tremendous promise for fuel-cell applications. When compared to 0.113 S/cm and 0.013 S/cm, respectively, of commercial Nafion^® 117 and Nafion^® ZrP membranes, the modified Nafion^® membrane with ammonia sulphate acid had the highest proton conductivity of 7.891 S/cm. When tested using a direct single-cell methanol fuel cell, it also had the highest power density of 183 mW cm^-2 which is better than commercial Nafion^® 117 and Nafion^® ZrP membranes.

Gelation Based on Host-Guest Interactions Induced by Multi-Functionalized Nanosheets

Host–guest interaction, being reversible and stimuli-responsive, is ideal to be applied to the design of hydrogels. We created a gelation system based on the host–guest interactions between the adamantyl groups and β-cyclodextrin (β-CD) polymer. N,N,N-trimethyl-1-adamantylammonium hydroxide (TriMAA) cations were attached to the pre-exfoliated α-zirconium phosphate (α-ZrP) nanosheets by ionic bonding through a displacement reaction with the exfoliating agents. The exfoliated α-ZrP nanosheets with adamantyl groups directly or indirectly attached to the surface act as reversible high-functionality crosslinkers within the β-CD polymer. The gelation occurred at a host-to-guest ratio of 1:10 or 1:5 at room temperature within minutes. The agents used to exfoliate α-ZrP can tailor the surface of the resultant α-ZrP nanosheets and the ionic strength of the system, which directly affects the further gelation results. Plus, the exfoliating agent cations may generate a host-and-guest interaction with the β-CD polymer as well. This gelation process without covalent bonding formation should help fellow researchers to better understand the gelation system and host–guest interactions.

Covalently immobilized ionic liquids on single layer nanosheets for heterogeneous catalysis applications

Covalently immobilized ionic liquids on sinlge layer α-zirconium phosphate nanosheets can serve as an efficient heterogeneous catalyst for various reactions, such as Knoevenagel condensation of benzaldehyde with ethyl cyanoacetate.

Exfoliated graphite nanoplatelets/poly(arylene ether nitrile) nanocomposites

In this work, we demonstrate a method for synthesis of exfoliated graphite nanoplatelets (xGnPs)/poly(arylene ether nitrile) (PEN) nanocomposites via an efficient in situ polymerization. The GnPs were treated by the ultrasonic bath to reduce the layers of the GnPs, where the PEN were intercalated subsequently. Therefore, the dispersion of xGnP in the PEN resin was enhanced through in situ polymerization, which was characterized and confirmed by scanning electron microscopy, transmission electron microscopy, and Fourier transform infrared spectroscopy. It was found that the tensile strength and modulus were greatly enhanced with the addition of xGnP. For 2.5 wt% of xGnP-reinforced PEN, the tensile strength and modulus were increased to 115 MPa and 3121 MPa, respectively. Owing to the well dispersion of xGnP, the low rheological percolation of 2.5 wt% for PEN nanocomposites was obtained. Besides, with 1 wt% of xGnP, the corresponding initial decomposition temperature ( Tin) increased from 451°C in pure PEN to 470°C. The addition of xGnP showed enhanced thermal stability of PEN nanocomposites, which demonstrated a promising method for preparing advanced polymer-based nanocomposites.

Designing Supported Ionic Liquids (ILs) within Inorganic Nanosheets for CO₂ Capture Applications

A new methodology was developed for the immobilization of ionic liquids (ILs) on α-zirconium phosphate (ZrP) and montmorillonite (MMT) single-layer nanosheets via a facile coassembly process. The coassembled inorganic nanosheet/1-n-butyl-3-methylimidazolium chloride (BMIMCl) hybrids were systematically characterized. The results showed that the ILs were successfully assembled with ZrP or MMT single-layer nanosheets to form an intercalated structure. The inorganic nanosheet/IL hybrids can serve as efficient CO2 absorbents. The CO2 sorption of BMIMCl could be made up to 21 times more efficient because of the high exposure of the functional groups of BMIMCl in the coassembled hybrids. CO2 was physically absorbed by the hybrids with a slow equilibrium time at lower temperatures, whereas higher temperatures allowed for faster diffusion and chemical absorption of CO2. The best CO2 capture capacities of the hybrids were 0.73 mmol/g at 60 °C for ZrP/BMIMCl and 0.42 mmol/g at 70 °C for MMT/BMIMCl.

Bi-axially oriented polystyrene/montmorillonite nanocomposite films

Polystyrene (PS)/montmorillonite (MMT) nanocomposite films were prepared by bi-axially stretching compounded and extruded PS/MMT nanocomposite sheets, resulting in an improved level of exfoliation and orientation during stretching.

Nanoparticles of ZrPO4 for green catalytic applications

Here we report the successful room temperature synthesis of zirconium phosphate nanoparticles (ZPNP) using the P123 tri-co-block polymer for the first time. The samples were characterized by SEM, TEM, XRD, TPD, and BET and were employed for fixation of CO2 on aniline to produce pharmaceutically important acetanilide under mild reaction conditions (150 °C and 150 Psi CO2 pressure).

Sulfonic acid-functionalized α-zirconium phosphate single-layer nanosheets as a strong solid acid for heterogeneous catalysis applications

Solid acids have received considerable attention as alternatives to traditional corrosive and hazardous homogeneous acids because of their advantages in practical applications, including their low corrosion of equipment and high catalytic activity and recyclability. In this work, a strong solid acid was prepared by anchoring thiol group terminated chains on layered α-zirconium phosphate (ZrP) single-layer nanosheets, followed by oxidation of thiol groups to form sulfonic acid groups. The obtained solid acids were thoroughly characterized and the results proved that sulfonic acid group terminated chains were successfully grafted onto the ZrP nanosheets with a high loading density. Such a strong solid acid based on inorganic nanosheets can be well-dispersed in polar solvents, leading to high accessibility to the acid functional groups. Meanwhile, it can be easily separated from the dispersion system by centrifugation or filtration. The strong solid acid can serve as an effective heterogeneous catalyst for various reactions, including the Bayer-Villiger oxidation of cyclohexanone to ε-caprolactone in the absence of organic solvents.

Intercalated polyfluorinated Pd complexes in α-zirconium phosphate for Sonogashira and Heck reactions

A direct method was used to effectively intercalate the short fluorous-ponytailed Pd complexes into the ZrP gallery, and the resulting Pd intercalated ZrP could be used as a recoverable catalyst for Sonogashira and Heck reactions.