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The hydrogenation of HCN to methylamine on Co(111) was used as a model reaction to study the hydrogenation of nitriles to primary amines. Density functional theory was used to characterize the reaction mechanism, and the results obtained were compared with those for the same reaction on Ni(111). Hydrogen cyanide adsorbs more strongly on Co(111) than on Ni(111), with an adsorption energy of -1.72 eV. The hydrogenation product, methylamine, is weakly adsorbed on Co(111), with an adsorption energy of -0.53 eV, which is very similar to the adsorption energy calculated on Ni(111). The calculated adsorption energies were used to explain the differences in activity and selectivity observed between nickel- and cobalt-based catalysts; the stronger adsorption of HCN on cobalt explains both the lower activity and the higher selectivity observed on this metal. Regarding the reaction mechanism, the hydrogenation reaction implies an imine intermediate (H2CNH) independent of whether hydrogen reacts with the carbon atom or with the nitrogen atom of the hydrogen cyanide molecule in the first step. The imine intermediate subsequently reacts to form H3CNH, which is finally hydrogenated to yield methylamine. The overall surface reaction is endothermic. Remarkably, comparing the HCN hydrogenation reaction mechanism on Co(111) and Ni(111) revealed no significant differences.

The Fischer–Tropsch synthesis represents a time-tested and fully proven technology for the conversion of synthesis gas (CO + H 2 ) into paraffins, olefins, and oxygenated hydrocarbons. Depending on the origin of the syngas, one speaks of gas-to-liquids, coal-to-liquids, biomass-to-liquids, or ‘anything’-to-liquids. Industrial Fischer–Tropsch plants run on iron or cobalt catalysts, in fixed-bed-, fluidized-bed-, or slurry bubble-column-type reactors. The Fischer–Tropsch synthesis has inspired a wealth of academic and industrial research, and questions as to the mechanism of the process, how to control the selectivity of the polymerization process, the surface structure of the active catalysts, and the reasons why the catalysts deactivate continue to be subjects of intense discussion at conferences and in the literature. This chapter presents an overview of the Fischer–Tropsch synthesis, its historical development, the different modes of operation, the reactor technology, the synthesis and characteristics of the catalysts, and the mechanism of the reactions.

Summary XPS and IR spectroscopy indicate that the electron density of the supported metal clusters in Pd/LTL catalysts is a function of the support acidity/alkalinity. In addition, the neopentane and propane hydrogenolysis TOF's increase with increasing support acidity from alkaline to acidic. The changes in spectroscopic and catalytic properties are due to electron deficient Pd on acidic supports, as previously proposed, and electron rich Pd on alkaline supports.

The adsorption and decomposition of ethanol on Rh(100) was studied as a model reaction to understand the role of C-OH functionalities in the surface chemistry of biomass-derived molecules. A combination of experimental surface science and computational techniques was used: (i) temperature programmed reaction spectroscopy (TPRS), reflection absorption infrared spectroscopy (RAIRS), work function measurements (Kelvin Probe-KP), and density functional theory (DFT). Ethanol produces ethoxy (CH3CH2O) species via O-H bond breaking upon adsorption at 100 K. Ethoxy decomposition proceeds differently depending on the surface coverage. At low coverage, the decomposition of ethoxy species occurs via β-C-H cleavage, which leads to an oxometallacycle (OMC) intermediate. Decomposition of the OMC scissions (at 180-320 K) ultimately produces CO, H2 and surface carbon. At high coverage, along with the pathway observed in the low coverage case, a second pathway occurs around 140-200 K, which produces an acetaldehyde intermediate via α-C-H cleavage. Further decomposition of acetaldehyde produces CH4, CO, H2 and surface carbon. However, even at high coverage this is a minor pathway, and methane selectivity is 10% at saturation coverage. The results suggests that biomass-derived oxygenates, which contain an alkyl group, react on the Rh(100) surface to produce synthesis gas (CO and H2), surface carbon and small hydrocarbons due to the high dehydrogenation and C-C bond scission activity of Rh(100).