Three dimensional arrays of hollow gadolinia-doped ceria microspheres prepared by r.f. magnetron sputtering employing PMMA microsphere templates

Preparation of macroporous gadolinia-doped ceria (CGO) films was attempted by r.f. magnetron sputtering. A polymethylmethacrylate (PMMA) microsphere film was fabricated as a template on a Pt-coated silicon substrate by dripping a PMMA microsphere aqueous dispersion onto the substrate. CGO was deposited onto the PMMA microspheres by sputtering; the PMMA microspheres were found to shrink during the sputtering, and thus the CGO also coated the surface of PMMA microspheres beneath the top layer of the film. Films (ca. 1.5 μm thick) consisting of three dimensional arrays of hollow CGO microspheres (ca. 700 nm in diameter) with large porosity were obtained after annealing the CGO/PMMA microsphere composite film.     

Meso–macroporous monolithic CuO–CeO2/γ/α-Al2O3 catalysts for CO preferential oxidation in hydrogen-rich gas: Effect of loading methods

Meso–macroporous alumina supported CuO–CeO₂ catalysts were prepared by citrate, urea combustion and impregnation methods. The effect of loading methods on the microstructure of the catalysts, the interaction between copper and ceria and the catalytic performance for preferential oxidation of CO in hydrogen-rich gases was investigated. The prepared monolithic catalysts were characterized by using techniques of N₂ adsorption and desorption, SEM, XRD, HRTEM and TPR. The results showed that the loading methods markedly influenced the catalyst structure and the catalytic performance. The citrate and urea combustion methods favored the formation of the interaction between copper and ceria. Compared with the urea combustion method, the citrate method led to smaller ceria particles on the alumina support. The meso–macroporous monolithic catalysts prepared by the citrate method maintained the structural characteristics of the highly active CuO–CeO₂ catalysts, and showed good catalytic performance in CO preferential oxidation in the simulated reformate gases containing water and CO₂.     

Macroporous and Antibacterial Hydrogels Enabled by Incorporation of Mg-Cu Alloy Particles for Accelerating Skin Wound Healing

Repair of severe skin tissue injury remains a great challenge and wound infection is still a formidable problem. In this study, new macroporous and antibacterial gelatin/alginate (SAG)-based hydrogels for wound repair were designed and developed based on in-situ gas foaming method and ion release strategy as a result of Mg-Cu particles degradation in the hydrogel matrix. The addition of Mg-Cu particles decreased the storage modulus of SAG, maintained its mechanical resilience and enhanced its water-absorbing capability. Moreover, the water vapor transmission rate of SAG added with 2 wt.% Mg-Cu (SAG-2MC) was 124% of that of medical gauze and 804% of commercial Tegaderm™ film dressing. The bacterial inhibition rates of SAG-2MC against S. aureus, E. coli and P. aeruginosa reached 99.9% ± 0.1%, 98.7% ± 1.2% and 98.0% ± 0.7%, respectively, significantly greater than those of the SAG hydrogel and Mg particle-modified hydrogels. In addition, SAG-2MC hydrogel was biocompatible and promoted cell migration. In vivo experiment results indicated that SAG-2MC significantly accelerated the skin wound healing in murine model as demonstrated by higher epidermis thickness, more collagen deposition and enhanced angiogenesis compared with SAG-0MC, SAG-2M and Tegaderm™ film. In summary, Mg-Cu particles have great potential to modulate the physiochemical and biological properties of SAG hydrogels. Mg-Cu particle-modified SAG hydrogels reveal significant promise in the treatment of severe skin wound or other soft tissue lesions.