Lanthanum (La) integration (at various nominal contents) in SBA-15 prepared under acidic medium was intended from corresponding direct nitrate addition during mesoporous silica formation. Materials were impregnated with Pt (1.5 wt%) and studied through several textural (N₂ physisorption), structural (XRD, TG-DTG), and surface (FTIR, STEM-HAADF, SEM-EDS, NH₃, and CO₂ TPD) instrumental techniques. Pt-impregnated solids were tested in phenol hydrodeoxygenation (HDO, T = 250 °C, 3.2 MPa, batch reactor, n-decane as solvent). Catalytic activity (in pseudo-first-order kinetic constant, k_HDO basis) was not directly related to Pt dispersion, which was not determined by nominal rare earth content. Determining the actual composition of modified SBA-15 materials is crucial in reaching sound conclusions regarding their physicochemical properties, especially when La modifier is directly added during mesoporous matrix formation, where efficient interaction among constituents could be difficult to get. Otherwise, results from some characterization techniques (N₂ physisorption and FTIR, for instance) could be misleading and even contradictory. Indeed, extant modifier precursors, when under SBA-15 synthesis conditions, could affect the properties of prepared materials even though they were absent in obtained formulations. Performing simple compositional analysis could eliminate uncertainties regarding the role of various modifiers on characteristics of final catalysts. However, several groups have failed in doing so.

Strategies followed to improve SBA-15 surface (essentially inert) included modifications by adding acidic or basic (or both) species during or after silica synthesis. Amphoteric properties are especially important, as some reactions (alcohol dehydration, for instance) require both types of sites to efficiently take place. In this work, single Zr (nominal 3, 5, and 10 wt%, as ZrOCl₂•8H₂O) direct addition during SBA-15 synthesis was used to impart amphoteric characteristics (as determined by NH₃ and CO₂ TPD) to mesostructured SiO₂ matrices. Additional materials characterization included textural (N₂ physisorption) and structural (XRD, FTIR, and UV–Vis spectroscopies, and HRTEM as well) studies. Actual solids composition was also determined (EDS). The degree of Zr incorporation into mesoporous silica was enhanced with nominal content in binary formulations, although not necessarily integrated into SBA-15 walls forming Zr-O-Si linkages. It seemed that single ZrO₂ domains (framework and extra-framework) could provide suitable amphoteric properties by significantly increasing the number and strength of both acid and basic sites (especially formulations containing nominal 5 wt% Zr), as to those over mesostructured silica matrices. Also, potentially deleterious strong acid sites were avoided. The binary oxides present great potential to be applied in reactions requiring vicinal acid–base pairs (alcohol dehydration, for instance).

Platinum reduction on Pt/C catalysts was studied on samples prepared by the impregnation method using different Pt precursors and reducing agents such as ethanol, sodium borohydride and ethanol-UV light (photo-assisted reduction), in order to compare the efficiency of the different reducing agents. The influence of the reduction level of the platinum species on the electrochemical behavior of these catalysts has been determined. The catalysts were characterized by X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM), X-ray photoelectron spectroscopy (XPS) and linear and cyclic voltammetry. The results show that the reduction level depends mainly on the platinum precursor. Moreover, it was found that the higher electrochemical activity was found using catalysts reduced with ethanol, whereas by using NaBH4 as the reducing agent, the total reduction of the platinum precursor is very difficult in same synthesis conditions. The analysis of the XPS results shows that samples reduced with ethanol presented the lower PtOx/Pt reduction ratio.