A composite heterogeneous photocatalyst based on silver bromide was prepared by a reaction of silver exchanged zirconium phosphate (ZrP) and HBr. The ZrP/AgBr composite containing 53 wt% AgBr was tested in the photocatalytic degradation of Rhodamine B (RhB) and exhibited higher catalytic activity with respect to pure AgBr. As a matter of fact, the time needed to achieve a percentage of chromophore cleavage of about 90% was 3 min for the composite versus the 30 min needed for pure AgBr. The ZrP/AgBr composite turned out to be stable for at least three consecutive cycles. The UV-Vis spectra of the RhB solution, recorded at different irradiation times, were also decomposed and the concentration of the species formed by de-ethylation and cleavage processes during photocatalysis were calculated; the data obtained for the AgBr-based catalysis were also compared with those for the AgCl-based catalysis, and the degradation mechanism was suggested for both catalytic systems.

A novel approach to mechanically reinforce polymer electrolyte membranes for fuel cells was developed by using hydrophilic zirconium phosphate (ZP) and hydrophobic fluoroalkyl zirconium phosphate (ZF) as a two-component mixed filler of a short-side-chain perfluorosulfonic acid (PFSA) membrane. Composite membranes filled with 10 wt% ZF and 5 wt% ZP have a strongly enhanced elastic modulus (E) and yield stress (σ_Y) with respect to the unmodified PFSA (ΔE/E ∼ 300%, Δσ_Y/σ_Y ∼ 95% at 70 °C and 80% relative humidity (RH)) and to the single filler membranes with optimized ZP or ZF loadings. In the RH range 50–95%, the in-plane conductivity of the mixed filler membrane is comparable with that of the unmodified PFSA, both at 80 and 110 °C, in spite of a lower water content. At 50% RH, the mixed filler membrane shows better fuel cell performance in H₂/air than the neat PFSA in terms of higher OCV, lower H₂ crossover and greater power density, with peaks of 0.82 W cm⁻² at 80 °C, and 0.70 W cm⁻² at 110 °C.

Surface-modified ZnAl layered double hydroxides (LDHs) were prepared by reaction of AgNO₃, with both ZnAlCl (LDH1) and ZnAlCO₃ exchanged on the surface with chloride anions (LDH3). In this way, AgCl nanoparticles with crystalline domains ranging from 40 to 100 nm were grown on the LDH surface. An additional sample was prepared by partial reduction of silver to obtain Ag@AgCl-LDH (LDH2). The composites were tested as catalysts in Rhodamine B (RhB) degradation, wherein LDH2 showed complete cleavage of RhB after 45 min of irradiation versus 70 min needed in the presence of AgCl. This time decreased to 35 min for LDH1 and 15 min for LDH3, underlining the role of the AgCl dimensions and anion in the interlayer region. Studies on the reactive species involved in the degradation process revealed that, for all catalysts, O₂·⁻ was the main active species, while, to some extent, holes contribute to the activity of the LDH3. Finally, the composites showed high bactericidal activity, under irradiation, against Escherichia coli, comparable with that of Gentamicin, the positive control. A synergic effect of silver released from the composites and the production of reactive oxygen species was considered.

CeO₂ nanoparticles were coated with polydopamine (PDA) by dopamine polymerization in water dispersions of CeO₂ and characterized by Infrared and Near Edge X-ray Absorption Fine Structure spectroscopy, Transmission Electron Microscopy, Thermogravimetric analysis and X-ray diffraction. The resulting materials (PDAx@CeO₂, with x = PDA wt% = 10, 25, 50) were employed as fillers of composite proton exchange membranes with Aquivion 830 as ionomer, to reduce the ionomer chemical degradation due to hydroxyl and hydroperoxyl radicals. Membranes, loaded with 3 and 5 wt% PDAx@CeO₂, were prepared by solution casting and characterized by conductivity measurements at 80 and 110 °C, with relative humidity ranging from 50 to 90%, by accelerated ex situ degradation tests with the Fenton reagent, as well as by in situ open circuit voltage stress tests. In comparison with bare CeO₂, the PDA coated filler mitigates the conductivity drop occurring at increasing CeO₂ loading especially at 110 °C and 50% relative humidity but does not alter the radical scavenger efficiency of bare CeO₂ for loadings up to 4 wt%. Fluoride emission rate data arising from the composite membrane degradation are in agreement with the corresponding changes in membrane mass and conductivity.

Zirconium phosphate phenylphosphonate nanoparticles improve mechanical properties and the stability of the proton conductivity of composite SPEEK membranes.