In this work, we present an investigation concerning the evaluation of the catalytic properties of Ni nanoparticles supported on ZrO2, SiO2, and MgAl2O4 for CO2 hydrogenation to methane. The supports were prepared by coprecipitation and sol-gel, while Ni was incorporated by impregnation (10–20 wt %). X-ray diffraction, nitrogen physisorption, temperature-programmed reduction, H2 pulse chemisorption, Raman spectroscopy, X-ray photoelectron spectroscopy, and transmission electron microscopy were the main characterization techniques employed. A laboratory fixed-bed reactor operated at atmospheric pressure, a temperature range of 350–500 °C, and a stoichiometric H2/CO2 molar ratio was used for catalyst evaluation. The most outstanding results were obtained with nickel catalysts supported on ZrO2 with CO2 conversions of close to 60%, and selectivity to methane formation was 100% on a dry basis, with high stability after 250 h of reaction time. The majority presence of tetragonal zirconia, as well as the strong Ni–ZrO2 interaction, were responsible for the high catalytic performance of the Ni/ZrO2 catalysts.

The sol-gel process is a friendly room temperature method to prepare transparent glasses in the form of monoliths, films, and fibers. The zinc oxide films have been obtained by sol-gel method, which are very important materials in the ceramic technology due to their piezoelectric properties and applications in various pressure transducers and acoustic-optic devices, surface and bulk acoustic wave devices, and solar cells. Structure and characteristic ultraviolet-blue emissions of amorphous and crystalline zinc oxide thin films-coated glass substrates by dip-coating deposition are explained by photoluminescence studies in this chapter.

Figure 1. Temporal evolution of sol-gel publications.

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Development of latent prints employing cyanoacrylate ester (CA) can be a multistep process including CA fuming and subsequent fluorescent staining to produce fingerprints of sufficient contrast for comparison work. To enable a single-step CA fuming-staining process, a selection of fluorophores have been developed as sublimation dyes in CA fuming. A greater array of such luminescent sublimation dyes would allow users greater flexibility in selecting a particular dye-CA combination to best suit their processing needs. Toward this end, six benzoic acid derivatives were evaluated for use as luminescent sublimation dyes under elementary CA fuming conditions using a single non-porous surface type and an inexpensive handheld UV lamp for excitation.Two benzoic acid derivatives, 2-hydroxybenzoic acid (salicylic acid) and 2-aminobenzoic acid (anthranilic acid), were identified as new potential luminescent sublimation dyes with stained fingerprints excited at 254 nm. The fluorescence intensity and stability of prints produced via the sublimation of CA with 2-hydroxybenzoic acid and 2-aminobenzoic acid were evaluated over approximately six weeks using image and statistical analysis.

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