01854nas a2200157   4500008004100000245010600041210006900147260000800216300001600224490000600240520125700246100001801503700002301521700003001544856012201574       2016                        eng d00aC-H activation of methane to formaldehyde on Ce1-xZrxO2 thin films: a step to bridge the material gap0 aCH activation of methane to formaldehyde on Ce1xZrxO2 thin films  cDEC  a3650–36560 v83 a<p>Ce1−xZrxO2 (CZ) thin films were prepared by a combination of sol–gel and spin-coating methods and were evaluated for the C−H activation of methane by using a molecular beam set-up with the aim to bridge the material gap. The C−H activation of methane begins at 950 K, and a Ce-rich CZ composition displays a high selectivity (4–12 %) to the partially oxidised product, formaldehyde. A 10–12 % selectivity towards HCHO with 1.6 % methane conversion was observed with methane-rich CH4/O2 reactant compositions at 1050 K. Short contact times, prevalent under molecular beam conditions, could be a possible reason for HCHO formation. Although combustion products were observed instantly upon shining the mixture of reactants on CZ surfaces, up to 20 s delay was observed before formaldehyde generation, which indicates that the oxygen vacancy migration contributes to the rate-determining step and the diffusion-controlled nature of the reaction. A burst in HCHO generation at the point of molecular beam opening, after beam-closed conditions, suggests that the diffusion of oxygen vacancies to the surface is the reason for HCHO formation. Kinetics results also indicate the necessity of reduction sites for HCHO generation.</p>1 aDubey, Anjani1 aKolekar, Sadhu, K.1 aGopinath, Chinnakonda, S.  uhttps://library.ncl.res.in/content/c-h-activation-methane-formaldehyde-ce1-xzrxo2-thin-films-step-bridge-material-gap01545nas a2200157   4500008004100000245008400041210006900125260000800194300001400202490000600216520098800222100001801210700002301228700003001251856010601281       2016                        eng d00aC-H activation of methane to syngas on MnxCe1-x-yZryO2 - a molecular beam study0 aCH activation of methane to syngas on MnxCe1xyZryO2 a molecular   cJUL  a2296-23060 v83 a<p>Mn-doped ceria zirconia thin films (MnxCe1-x-yZryO2, MCZ) were employed as flat model catalyst surfaces for CH4 activation. MCZ films exhibit characteristics of single crystal and powder materials, such as smooth surfaces and porosity. From molecular-beam studies, it has been identified that the oxygen storage capacity increases with Mn content. Mutually exclusive observation of H2O or a mixture of products (CO2+ CO + H-2) occurs, when the reactants was allowed to react directly on MCZ, underscoring their formation or prevention (and consumption), respectively. The results suggest that there is competition and cooperation among different elementary reactions under complementary conditions. From a significant partial oxidation of CH4 through C-H activation, it is found that formation of syngas begins at 700 K and the reaction rate increases with increasing temperature. Kinetic evidences indicate that the reaction proceeds through a combustion-reformation pathway.</p>1 aDubey, Anjani1 aKolekar, Sadhu, K.1 aGopinath, Chinnakonda, S.  uhttps://library.ncl.res.in/content/c-h-activation-methane-syngas-mnxce1-x-yzryo2-molecular-beam-study