Hydrogenation on metals

Catalysis and the Adsorption of Hydrogen on Metal Catalysts Otto Beeck... 

Trasatti S. 1972. Electronegativity, work function, and heat of adsorption of hydrogen on metals. J Chem Soc Faraday Trans I 68 229-236. 

Whereas determination of chemisorption isotherms, e.g., of hydrogen on metals, is a means for calculating the size of the metallic surface area, our results clearly demonstrate that IR studies on the adsorption of nitrogen and carbon monoxide can give valuable information about the structure of the metal surface. The adsorption of nitrogen enables us to determine the number of B5 sites per unit of metal surface area, not only on nickel, but also on palladium, platinum, and iridium. Once the number of B5 sites is known, it is possible to look for other phenomena that require the presence of these sites. One has already been found, viz, the dissociative chemisorption of carbon dioxide on nickel. 

Thomas KM. Adsorption and desorption of hydrogen on metal-organic framework materials for storage applications comparison with other nanoporous materials, Dalton Trans 2009, 2009,1487-1505. 

Indeed the distinction between the mechanism for the reaction of hydrocarbons with hydrogen on metals compared to oxides may be that the metals have open the above avenue for a,)3 exchange while the reaction on oxides is restricted to a single atomic center 37). 

The conclusions on the mechanism of the double bond hydrogenation on metallic catalysts can be summarized as follows (1) with respect to structure effects on rate, all transition metals behave similarly (2) the reactivity of the unsaturated compounds is governed mostly by the number and size of the substituents on the carbon atoms of the double bond through their influence on adsorptivity (3) the electronic nature of the substituents plays a minor if any role. 

A term used to refer to any chemical process whose rate depends upon saturation of a binding site. Rate saturation is observed in enzyme kinetics, metabolic transport, host-guest reactions, and even heterogenous catalysis such as hydrogenation on metallic surfaces of platinum and nickel. 

The Adsorption of Hydrogen on Metal Films Partially Covered with... 

Reactions which may occur on sites consisting of one or two atoms only on the surface of the catalyst are generally known as facile reactions. Reactions involving hydrogenation on metals are an example. Eor such reactions, the state of dispersion or preparation methods do not greatly affect the specific activity of a catalyst. In contrast, reactions in which some crystal faces are much more active than others are called structure sensitive. An example is ammonia synthesis (discovered by Fritz Haber in 1909 (Moeller 1952)) over Fe catalysts where (111) Fe surface is found to be more active than others (Boudart 1981). Structure-sensitive reactions thus require sites with special crystal structure features, which... 

To explain the phenomena of activated adsorption, Lennard-Jones (9) in 1935 proposed a scheme for the adsorption of hydrogen on metal... 

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