Hydrogen evolution catalyst

The dehydrogenation of decalin to naphthalene has been investigated on Pt/C, Pt/A1(0H)0 and Pt/Al203 catalysts. The maximum conversion of decalin on 3.9% Pt/C, which did not repel decalin, was observed at 483 K under the conditions of 0.3 g of the catalyst and 1ml of decalin, which was corresponded to the liquid film state under reactive distillation conditions. However such a maximum was not observed on Pt/Al(OH)0 and Pt/Al203, which repelled decalin. Furthermore it was found that the reaction temperature, at which the maximum hydrogen evolution was observed on Pt/C, was shifted from the boiling point of decalin to that of naphthalene with increasing the amormt of naphthalene in the reaction solution. 

Fig. 2 Hydrogen evolution at various reaction times on 5 wt. % Pt/C (A) and on various catalysts at 483 K (B).

Two different types of zinc-porphyrins coordinated diiron complex act as catalysts for the photochemical reduction hydrogen evolution from water. In this system... 

Hinnemann B, Moses PG, Bonde J, Jorgensen KP, Nielsen JH, Horoh S, Chorkendorff I, Nprskov JK. 2005. Biomimetic hydrogen evolution M0S2 nanoparticles as catalyst for hydrogen evolution. J Am Chem Soc 127 5308-5309. 

The stereochemistry of electrochemical reduction of acetylenes is highly dependent upon the experimental conditions under which the electrolysis is carried out. Campbell and Young found many years ago that reduction of acetylenes in alcoholic sulfuric acid at a spongy nickel cathode produces cis-olefins in good yields 126>. It is very likely that this reduction involves a mechanism akin to catalytic hydrogenation, since the reduction does not take place at all at cathode substances, such as mercury, which are known to be poor hydrogenation catalysts. The reduction also probably involves the adsorbed acetylene as an intermediate, since olefins are not reduced at all under these conditions and since hydrogen evolution does not occur at the cathode until reduction of the acetylene is complete. Acetylenes may also be reduced to cis olefins in acidic media at a silver-palladium alloy cathode, 27>. 

Production of hydrogen from an inexhaustible somce, water, by a cheaper route has been under extensive investigation in recent years (Koca and Sahin, 2003). The requirement for the photoproduction of hydrogen using a semiconductor is the need for a hydrogen evolution catalyst on a semiconductor surface as reported by marty... 

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