Metal-Containing Pd and Cu and Bimetallic Pd—Cu Catalytic Systems Based on HZSM-5 Zeolite

Palladium- and copper-containing HZSM-5 zeolites with different metal loadings, together with Pd–Cu and Cu–Pd bimetallic zeolite systems, were prepared by ion-exchanging HZSM-5 zeolite with metal–ammine complex cations. The catalytic activity of such materials in CO oxidation was investigated under flowing conditions using various gas mixtures (0.5–2% CO, 20% O 2 and 78–79.5% He). The dependence of the activity of the Cu–Pd system on the CO content in the gaseous mixture was observed. The influence of the catalytic properties on the reduction conditions employed for the metal-containing zeolites was investigated. Correlations between the catalytic activity and the intensity of the N–H band in the IR spectra characteristic of the various Pd/Cu–ammine complexes incorporated in the zeolite matrix were demonstrated

Catalytic Activity in CO Oxidation of MnOx Supported on Oxide and Zeolite Carriers

Catalytic activity in CO oxidation was investigated for MnOx-containing materials, prepared by impregnation of SiO2, Al2O3 and zeolites (ZSM-5, ERI). The catalysts were characterized by temperature-programmed reduction (TPR) by hydrogen, diffuse-reflectance UV–Vis (DR UV–Vis) and infra-red (IR) spectroscopy of adsorbed CO. Effect of the previous treatment of the MnOx-containing systems on the catalytic performance has been established. Higher catalytic activity in CO oxidation of the materials treated with air as compared with treated with hydrogen can be explained by presences of manganese ions in +3 and +4 oxidation states. 3%Mn-SiO2 previously treated with air at 350 °C is found to be the most active catalyst among the studied ones. MnOx, CO oxidation, TPR, IR of adsorbed CO, DR UV–Vi

Adsorption and Catalytic Properties of Co/ZSM-5 Zeolite Catalysts for CO Oxidation

Studies were made of the adsorption and acidic properties, the coordination state of the Co ion in Co 2 +, Co 3 +-containing ZSM-5 zeolite systems and the catalytic activity of these zeolites in CO oxidation. A correlation was established between the catalytic activity of these Co-containing zeolites and the number of Brönsted acid sites on the surface and in the system bulk as obtained by different methods. The content of various forms of Co ion coordination states and the ratio of Brönsted to Lewis acidic sites at the surface of the Co-containing zeolites defined their activity in CO oxidation

Secondary structure of muramyl dipeptide glycoside in pristine state and immobilized on nanosilica surface

Fourier transform infrared spectroscopy (FT-IR) and temperature programmed desorption mass spectrometry (TPD-MS) data of O-glycoside MDP in pristine and immobilized on silica surface states indicate that O-glycoside MDP binds to the silica surface by means of carboxylic and NH moieties of isoglutamine. Moreover, pyrolysis of O-glycoside MDP on the silica surface proceeds through formation of additional product 3-iminopyridine-2(3H)-one, which identified in mass spectra as molecular ion with m/z 108 and its fragment ions with m/z 79, 77, 51. FTIR and TPD-MS data confirm existence of a MDP first β-turn on the silica surface resulting from the formation of a hydrogen bond between the NAc carbonyl and the L-Ala NH for MDP and its analogs, as reported previously