Low-temperature CO oxidation by transition metal polycation exchanged low-silica faujasites

Spectroscopic Investigation of Titania‐Supported Gold Nanoparticles Prepared by a Modified Deposition/Precipitation Method for the Oxidation of CO

“…For this process, finely dispersed nanoparticles are very important because bulk gold proved chemically inactive . Moreover, understanding the active electronic state is fundamental to explain the mechanisms involved in the oxidative process . Tests were carried out at room temperature without the addition of water to rule out the influence of its variation .…”

Reactive Adsorption of Sulfur Compounds on Transition Metal Polycation‐Exchanged Zeolites for Desulfurization of Hydrocarbon Streams

“…[17,21,42] Thee xperimental procedures for the preparation of the majority of the Tr Mp olycation-exchanged samples used in the present study were described in Refs. [20,21,23].A sa ne xample,t he preparation of (Mn) p LSF samples with varied Mn cation-exchange degrees is given below in greater detail.…”

“…Ther esults confirm that the crystalline structures of the zeolites do not undergo any essential destruction through the ion-exchange procedure.I ts hould be noted also that the general surface areas of the studied samples,w hich were measured by nitrogen adsorption at À196 8C, remained fixed in the 550-650 m 2 g À1 range for all exchanged and dealuminated samples.I ti sa lso important to note that the study of the Cu and Mn polycation-exchanged samples by XANES [21] and electron paramagnetic resonance (EPR) spectroscopy [20] showed that all of the copper and manganese species in the polycation-containing samples were found in the 2 + + oxidation state,a nd separated hydroxides were not produced.…”

“…Such polycations have the general formula [TrM α O β ] m n + , in which α =2–8, β =0–4, m =2–6, and n =2 or 3. Owing to the high dispersity and nanostructures of the TrM polycation moieties (0.4–1.6 nm) along with the excess of oxygen in the TrM superoxides, remarkable adsorption capacities and catalytic activities of the corresponding zeolites towards various substances were reported . The authors also found that the reactive adsorption of 1,3‐butadiene with the dimerization of the substrate over some TrM polycation‐exchanged low‐silica faujasites (LSF) is responsible for the enhanced adsorption capacity of the applied adsorbent–catalysts …”

“…[16,17] Such polycations have the general formula [TrM a O b ] m n+ + ,i n which a = 2-8, b = 0-4, m = 2-6, and n = 2o r3 .O wing to the high dispersity and nanostructures of the Tr Mp olycation moieties (0.4-1.6 nm) along with the excess of oxygen in the Tr Ms uperoxides, [14,18] remarkable adsorption capacities and catalytic activitieso ft he correspondingz eolitest owards various substances were reported. [11,19,20] Thea uthors also found that the reactive adsorption of 1,3-butadiene with the dimerization of the substrate over some Tr Mp olycation-exchanged low-silica faujasites (LSF) is responsible for the enhanced adsorption capacity of the applied adsorbent-catalysts. [21] Accordingly, it is reasonable to assume that the unusually high adsorption values for sulfur compounds displayed by Cu, Zn, and Mn polycation-exchanged zeolites [22,23] may result from as imilar catalytic-adsorption action.…”