In recent past development of silver nanoparticles and their application in the treatment of wastewaters is becoming a major area of research. It is mainly applicable to the removal of three major pollutants like pesticides, heavy metals, and microorganisms. Variety of synthesis techniques have been reported for preparation and characterization of silver nanoparticles. In our research, we synthesized Ag nanoparticles supported on ZrO2 and ZrO2-CeO2 by a “deposit-precipitation method” as the first step and later sequentially synthesized Ag-Au supported on ZrO2 and ZrO2-CeO2 by Redox method. Catalysts were evaluated in catalytic wet air oxidation (CWAO) of methyl tert-butyl ether and phenol. The CWAO is a liquid phase process for the treatment of organic pollutants operating at temperatures in the range of 100–325°C at 5–200 bar pressures. The selectivity and efficient of catalysts were evaluated by total organic carbon (TOC) and high-performance liquid chromatograph (HPLC). Ideally, the total mineralization of pollutants into CO2 and H2O is preferred.

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).

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 (alcohols dehydrations, for instance) require of both type 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). Degree of Zr incorporation to mesoporous silica was enhanced with nominal content in binary formulations, although not necessarily integrated in 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 number and strength of both acid and basic sites (especially formulation 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-basic pairs (alcohols dehydration, for instance).