Zirconia-Supported Silver Nanoparticles for the Catalytic Combustion of Pollutants Originating from Mobile Sources

Abstract

This work presents the physicochemical characterization and activity of zirconia-supported silver catalysts for the oxidation of pollutants present in diesel engine exhaust (propane, propene, naphthalene and soot). A series of silver-supported catalysts AgxZ (x = 1, 5 and 10 wt.%, Z = zirconia) were prepared, which were studied by various characterization techniques. The results show that silver is mainly found under the form of small metal nanoparticles (<10 nm) dispersed over the support. The metallic phase coexists with the AgOx oxidic phases. Silver is introduced onto the zirconia, generating Ag–ZrO2 catalysts with high activity for the oxidation of propene and naphthalene. These catalysts also show some activity for soot combustion. Silver species can contribute with zirconia in the catalytic redox cycle, through a synergistic effect, providing sites that facilitate the migration and availability of oxygen, which is favored by the presence of structural defects. This is a novel application of the AgOx–Ag/ZrO2 system in the combustion reaction of propene and naphthalene. The results are highly promising, given that the T50 values found for both model molecules are quite low.

Promoting Effect of Palladium on ZnAl2O4-Supported Catalysts Based on Cobalt or Copper Oxide on the Activity for the Total Propene Oxidation

“…The temperature of the catalytic bed was monitored by a k-type thermocouple and the temperature was varied from 150 • C to 600 • C at 1.6 • C/min. A schematic diagram of the reaction systems has been reported in a previous work [44].…”

Propane and Naphthalene Oxidation over Gold-Promoted Cobalt Catalysts Supported on Zirconia

“…The separation of products was performed with an Alltech CTRI concentric column. A schematic diagram of the reaction system was reported in a previous work [24]. Propane conversion was calculated using the expression:…”

“…Previous studies carried out by our research group showed that tetragonal phases can be generated by adding various cations of interest in catalysis (Co(II), Cu(II), Ni(II), or Ag(I)) to a zirconia hydrogel. In addition, the effect of the addition of cations and their oxides on the redox capacity of catalysts for hydrocarbon oxidation reactions was shown [23,24].…”

Reusable Nano-Zirconia-Catalyzed Synthesis of Benzimidazoles and Their Antibacterial and Antifungal Activities

“…Nitrogen- and sulfur-based heterocyclic compounds show a wide variety of biological activity as antitumor, antibacterial, antifungal, and antiviral agents [ 23 ]. The preparation of several biologically active benzimidazole and benzotriazole derivatives has been described in previous reports [ 24 ]. Recently, Salauddin et al reported a review on benzimidazoles, biologically active compounds, which were discussed in terms of antimicrobial, antiviral, anticancer, antiprotozoal, anti-inflammatory, and analgesic activities [ 25 ].…”