@article{scholars11814,
         journal = {Journal of Supercritical Fluids},
       publisher = {Elsevier B.V.},
           pages = {8--13},
            year = {2019},
           title = {Catalytic oxidative coupling of methane in supercritical water: Investigations on a catalytically active species},
          volume = {144},
            note = {cited By 6},
             doi = {10.1016/j.supflu.2018.07.001},
             url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85054344899&doi=10.1016\%2fj.supflu.2018.07.001&partnerID=40&md5=6a85d655fa2aba2573d2986444ba3681},
        keywords = {Batch reactors; Binding energy; Catalysts; Manganese oxide; Methane; Petroleum prospecting; Silica; Sodium compounds; Transition metal oxides; Transition metals; Zirconia, Active surfaces; Catalytically active species; Feed concentration; Methane coupling; Oxidative coupling of methane; Oxidative coupling of methanes (OCM); Supercritical water; ZrO2 synergy, Molecular oxygen},
        abstract = {Catalyst survey for oxidative coupling of methane (OCM) under supercritical water (SCW) environment at 658 K and 26 MPa using an 8.8-mL batch reactor and H2O2 as a molecular oxygen source was performed at a feed concentration molar ratios of 0.10 CH4/H2O and 0.15 O2/CH4. First and second transition metal oxides (V, Cr, Co, Cu, Zr and Mo) and some lanthanide oxides (La and Ce) showed relatively high OCM activities of ca. 0.5{\^a}??1  C yield at a very low catalyst loading of 0.05 g. Exploration of catalyst formulations found that oxides of transition metals combined with ZrO2 were effective, with MnO2{\^a}??ZrO2 showing a high synergy effect giving almost twice as much methane coupling yield. The OCM activity was correlated with the surface amount of a low 1s binding energy (O1s, 526{\^a}??527 eV) oxygen species on the catalyst, as well as its energy separation from the lattice oxygen. In terms of this oxygen species, SCW-OCM activity of Mn/Na2WO4/SiO2, known as a good gas phase OCM catalyst and also showed a high turnover efficiency for SCW-OCM was further improved by supporting Mn/Na2WO4 on ZrO2 instead of SiO2. {\^A}{\copyright} 2018 Elsevier B.V.},
          author = {Hassan, M. A. and Miyao, T. and Komiyama, M.},
            issn = {08968446}
}