Search

We report on the “one step─one pot” synthesis of chain-lengthened aliphatic amines and nitriles from CO/H2/NH3 gas feeds using potassium-promoted Co/MnOx catalysts prepared via MOF-type (metal orga...

We study the hydrogenation of CO under ambient pressure conditions over a Co-MnOx model catalyst using chemical transient kinetics (CTK) under calibrated molecular flow conditions. Alkanes and alke...

Monodisperse Fe(0) nanoparticles with diameters between 1.8 and 9.0 nm were prepared from organometallic {Fe[N(SiMe3)2]2}2 and intercalated into mesoporous MCF-17 silica. We observed high turnover frequencies of the catalytic CO hydrogenation; they increased with Fe particle size. Methane and short-chain olefin selectivities were highest for small particles, while the opposite trend applied to long-chain terminal olefins and oxygenates. The Anderson–Schulz–Flory chain lengthening probabilities were found to increase with Fe particle size for both paraffins and terminal olefins. Reaction-induced sintering of the metal particles was limited and could be explained by the transformation of Fe(0) precursors into (mainly) Fe-carbides. The results cast new light on the structure sensitivity of the catalytic CO hydrogenation.

Co nanoparticles of well-defined size were synthesized by temperature-controlled injection of Co2(CO)8 into dichlorobenzene. After intercalation into mesoporous MCF-17 and temperature-programmed oxidation, Co3O4/MCF-17 model catalysts were obtained with cobalt oxide particle sizes varying between 3.5 and 12.2 nm. We demonstrate here the occurrence of a distinct particle size effect for the CO oxidation. Maximum reaction rates of about 0.77 nm–2 s–1 at 150 °C were observed for Co3O4 particles with a size in the range of 5 to 8 nm. The reaction rates decreased for either smaller or larger sizes. X-ray photoelectron spectroscopy allowed establishing a clear correlation between the Co3+ trivalent oxidation state and the CO oxidation rate.