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Catalytic and stoichiometric hydrogen formation by UV irradiation of sodium and zinc sulfide
Author(s) -
Kisch Horst,
Fernández Asuncion,
Millini Roberto
Publication year - 1986
Publication title -
chemische berichte
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.667
H-Index - 136
eISSN - 1099-0682
pISSN - 0009-2940
DOI - 10.1002/cber.19861191122
Subject(s) - chemistry , formate , inorganic chemistry , photochemistry , sodium formate , catalysis , hydrogen , flash photolysis , aqueous solution , radiolysis , hydrogen sulfide , ethylene glycol , methanol , sulfur , organic chemistry , reaction rate constant , kinetics , physics , quantum mechanics
UV irradiation (λ ⩾ 248 nm) of sodium sulfide in aqueous solution leads to hydrogen and disulfide, Φ(H 2 ) = 0.34 at λ = 254 nm. Light absorption occurs by HS − which affords the solvated electron and the HS radical as indicated by flash photolysis and pulse radiolysis. In the presence of formate, hydrogen evolution becomes catalytic with respect to HS − , Φ(H 2 ) = 0.12 at λ = 254 nm. Deuteration experiments indicate that hydrogen formation occurs partially via hydrogen atoms which abstract hydrogen from formate. The latter is finally oxidized to give carbonate. When methanol is used instead of formate, there are produced ethanol, ethylene glycol, methane, and formaldehyde in addition to hydrogen and carbonate. It is shown that the direct homogeneous photolysis of HS − may contribute significantly to the heterogeneous zinc sulfide‐catalyzed hydrogen evolution in the presence of sodium sulfide when performed in quartz vessels.