Structurally Complex Molybdenum Oxide Model Catalysts for the Selective Oxidation of Propene

Nanocatalysis: Mature Science Revisited or Something Really New?

“…[113] In order to arrive at this result it was essential to investigate the solution-phase chemistry of molybdates. [120][121][122] Precipitation conditions were chosen such that the synthons coexisted with the linker units in solution. The substantial analytical effort that was required to find the region of coexistence of homonuclear building blocks and linkers prevented systematic optimization with respect to larger length scales, the connectivity of the network, and the reactivity of the initial precipitate to give different crystal sizes and shapes.…”

Nanostructuring of binary molybdenum oxide catalysts for propene oxidation

“…Briefly, a stirred 4l reactor is equipped with computer-controlled pump systems and a monitoring system for pH and conductivity, allowing isothermal precipitation reactions to be conducted with time, pH, or conductivity as control variable, as described by Abd Hamid et al [17]. The samples here were obtained in the decreasing pH mode using 0.5 M ammonium heptamolybdate (AHM) for sample 1 and 0.2 M AHM for sample 2 and 1 M HNO 3 as precipitation agent.…”

“…A mixture of molybdenum oxide hydrates, of hexagonal MoO 3 , and of a family of supramolecular oxo clusters familiar in synthetic inorganic chemistry [14][15][16] are the primary products. We have recently studied the conditions and selection mechanisms that allow controlling the species obtained by aqueous precipitation [17]. There is strong evidence from in situ studies that o-Mo is an active catalyst if it is suitably defected.…”

Characterization of nanostructured binary molybdenum oxide catalyst precursors for propene oxidation

“…Ammonium heptamolybdate tetrahydrate dissolved in bidestilled water in order to obtain a Mo concentration of 0.7 mol L −1 is used as starting material. As precipitation agent, HNO 3 1 mol L −1 is applied at 303 K (Hamid et al ., 2003; Wagner et al ., 2004). The samples are filtered and dried in an exsiccator over dry gel.…”