02785nas a2200289 4500008004100000022001400041245018600055210006900241260006100310300001000371490000800381520172800389653001602117653001102133653001302144653002202157653002402179100002902203700002102232700002002253700002102273700001302294700001702307700001802324700002802342856012502370 2008 eng d a1011-372X00aSelective oxidation of ethane over Mo-V-Al-O oxide catalysts: insight to the factors affecting the selectivity of ethylene and acetic acid and structure-activity correlation studies0 aSelective oxidation of ethane over MoVAlO oxide catalysts insigh a233 SPRING STREET, NEW YORK, NY 10013 USAbSPRINGERcFEB a39-510 v1213 a

Catalysts of general formula, MoVAlOx were prepared with the initial elemental composition of 1:0.34:0.167 (Mo:V:Al) at a pH value in the range of 1-4. The elemental analysis showed that the final composition of the catalysts is pH dependant. The performance of the catalysts was tested for selective oxidation of ethane to give ethylene and acetic acid. While all of them were active for ethane oxidation with a moderate conversion, the catalyst prepared at pH 2 showed a highest activity with 23% ethane conversion and a combined selectivity of 80.6% to ethylene and acetic acid. The catalyst prepared at pH 4 was least selective to ethylene and acetic acid. Various techniques like powder XRD, SEM, Raman, UV-Vis and EPR were used to characterize the catalysts and to identify the active phases responsible for the selective oxidation of ethane. The powder XRD data showed that the catalysts prepared at pH 1 and 2 contain mainly of MoO3 and MoV2O8 along with traces of Mo4O11. The amount of MoO3 was slightly higher in the catalyst prepared at pH 1. However, the catalyst prepared at pH 3 contains mainly of MoV2O8 with no trace of MoO3. The catalyst prepared at pH 4 showed V2O5 as the major phase along with MoVAlO4 phase. The Raman data corroborated the XRD results. EPR and UV-Vis studies indicated the presence of traces of V-4 in pH 1 and 2 catalysts and significant amount of Mo5+ in all the catalysts. Thus, the high activity and selectivity to ethylene and acetic acid are attributed to the presence of MoV2O8 phase and other reduced species like Mo4O11 phase supported on MoO3. The presence of V and Mo ions in a partially reduced form seems to play a crucial role in the selective oxidation of ethane.

10aAcetic acid10aethane10aEthylene10amixed metal oxide10aSelective oxidation1 aSankaranarayanan, T., M.1 aIngle, Rohit, H.1 aGaikwad, T., B.1 aLokhande, S., K.1 aRaja, T.1 aDevi, R., N.1 aRamaswamy, V.1 aManikandan, Palanichamy uhttps://library.ncl.res.in/content/selective-oxidation-ethane-over-mo-v-al-o-oxide-catalysts-insight-factors-affecting-001970nas a2200241 4500008004100000022001400041245013700055210006900192260000800261300001600269490000600285520111900291653002101410653001301431653001201444653001801456653002201474100002301496700002301519700002501542700002901567856013201596 2020 eng d a2365-654900aCooperative acid-base sites of solid Ba-Zr mixed oxide catalyst for efficient isomerization of glucose to fructose in aqueous medium0 aCooperative acidbase sites of solid BaZr mixed oxide catalyst fo cOCT a12505-125130 v53 a

Efficient and highly selective isomerization of glucose to fructose was achieved by using the inexpensive Ba-Zr mixed metal oxide catalyst. Catalyst was prepared by varying Ba-Zr ratios using co-precipitation method. Various phases formed, planes exposed, morphology, elemental composition and particle size, basic site density and strength, oxidation state of elements were well studied by using various characterization techniques. The XRD analysis clearly indicates the presence of Ba+2 and Zr+4 in the form of BaO, ZrO2 and BaZrO3 phases. The SEM and HR-TEM images indicate that, Ba-Zr (2 : 1) catalyst prepared showed uniform morphology with spherical and rod-shaped particles ranging from 300 to 600 nm. Under the optimized reaction conditions Ba-Zr (2 : 1) catalyst exhibited excellent results in terms of 57 % of glucose conversion with 89 % selective formation of glucose. The presence of both acidic as well as basic sites play vital roles in activating the substrate molecules to selectively yield fructose. Ba-Zr (2 : 1) catalyst showed excellent recyclability performance up to four recycles.

10aCo-precipitation10afructose10aglucose10aisomerization10amixed metal oxide1 aShaikh, Samrin, S.1 aPatil, Chetana, R.1 aKondawar, Sharda, E.1 aRode, Chandrashekhar, V. uhttps://library.ncl.res.in/content/cooperative-acid-base-sites-solid-ba-zr-mixed-oxide-catalyst-efficient-isomerization-glucose02015nas a2200217 4500008004100000022001400041245012400055210006900179260000800248300001200256490000700268520127400275653000901549653002201558653000801580653001301588100002201601700002401623700001801647856013201665 2021 eng d a1944-824400aEfficient electrochemical oxygen reduction to hydrogen peroxide by transition metal-doped silicate Sr0.7Na0.3SiO3-delta0 aEfficient electrochemical oxygen reduction to hydrogen peroxide  cJAN a382-3900 v133 a

Electrochemical oxygen reduction in a selective two-electron pathway is an efficient method for onsite production of H2O2. State of the art noble metal-based catalysts will be prohibitive for widespread applications, and hence earth-abundant oxide-based systems are most desired. Here we report transition metal (Mn, Fe, Ni, Cu)-doped silicates, Sr0.7Na0.3SiO3-delta, as potential electrocatalysts for oxygen reduction to H2O2 in alkaline conditions. These novel compounds are isostructural with the parent Sr0.7Na0.3SiO3-delta and crystallize in monoclinic structure with corner-shared SiO4 groups forming cyclic trimers. The presence of Na stabilizes O vacancies created on doping, and the transition metal ions provide catalytically active sites. Electrochemical parameters estimated from Tafel and Koutechy-Levich plots suggest a two-electron transfer mechanism, indicating peroxide formation. This is confirmed by the rotating ring disc electrode method, and peroxide selectivity and Faradaic efficiency are calculated to be in the range of 65-82% and 50-68%, respectively, in a potential window 0.3 to 0.6 V (vs RHE). Of all the dopants, Ni imparts the maximum selectivity and efficiency as well as highest rate of formation of H2O2 at 1.65 mu mol s(-1).

10aH2O210amixed metal oxide10aORR10asilicate1 aThundiyil, Shibin1 aKurungot, Sreekumar1 aDevi, Nandini uhttps://library.ncl.res.in/content/efficient-electrochemical-oxygen-reduction-hydrogen-peroxide-transition-metal-doped-silicate01866nas a2200241 4500008004100000022001400041245011300055210006900168260000800237300001400245490000800259520106200267653001801329653002101347653001301368653001301381653002201394100002501416700002201441700002601463700000501489856013001494 2023 eng d a0008-403400aActivity performance and kinetics for glycerol carbonylation with urea over Zn-Co mixed metal oxide catalyst0 aActivity performance and kinetics for glycerol carbonylation wit cAPR a2075-20930 v1013 a

Efficient carbonylation of glycerol using urea with Zn-Co mixed metal oxide (MMO) catalyst has been achieved. Various methods of catalyst preparation were explored for glycerol carbonate (GC) synthesis. The optimized method of catalyst preparation was found to be co-precipitation (CP) with a Zn:Co ratio of 70:30, achieving 81% glycerol conversion with 97% GC selectivity. X-ray diffraction (XRD) studies revealed the formation of ZnO, Co-3 O-4, and spinel ZnCo2O4 phases. Thermal treatment given to the catalyst allows insertion of Zn cations into Co3O4 lattice forming ZnCo2O4 phase which was also evidenced in X-ray photoelectron spectroscopy (XPS) and Raman spectroscopy. Herein, for the first time, reaction kinetics was studied to propose the rate equation, based on which a plausible reaction pathway is proposed involving two-site adsorption of glycerol (basic site) and urea (acidic site), which undergo carbonylation followed by cyclization into GC. A recycle study and hot filtration test have proven the reusability of the catalyst.

10aCarbonylation10acyclic carbonate10aGlycerol10akinetics10amixed metal oxide1 aKondawar, Sharda, E.1 aKasar, Gaytri, B.1 aKhatua, Angshuman, S.1 a uhttps://library.ncl.res.in/content/activity-performance-and-kinetics-glycerol-carbonylation-urea-over-zn-co-mixed-metal-oxide