New Metal Oxide Composite Materials as Efficient Catalysts of Partial Oxidation of Methane

Аннотация

Single-phase complex oxides Nd_2 – yCa_yCo_xNi_1 – xO₄ have been synthesized for the first time. Composites prepared by the reduction of these compounds with hydrogen and containing Nd₂O₃, CaO, and cobalt and nickels metals have been used for the first time as catalysts of the partial oxidation of methane. The maximal methane conversions (97%) and syngas yields (96%) at 900°С have been detected in the presence of the composite obtained from Nd_1.5Ca_0.5NiO₄. At T < 850°C, the nickel–cobalt composite synthesized from Nd_1.3Ca_0.7Co_0.4Ni_0.6O₄ turned out to be more selective in the formation of syngas. Decreasing the partial oxidation temperature from 900 to 750°С leads to the oxidation of metallic nickel and cobalt to oxides and to partial resynthesis of complex oxides with perovskite and K₂NiF₄ structures. The observed differences in temperature dependence of the catalytic properties of composites with various Ni/Co ratios can be associated with the participation of complex oxides in catalysis of the partial oxidation of methane at low temperatures.