Electrochemical investigations of benzoylisothiocyanate, pyrollidine-1-dithiocarboxylic acid sodium salt dihydrate, rubeanic acid, 2-thiazoline-2-thiol, and thiourea, measured in acetonitrile, were performed to ascertain which substances are thermodynamically suitable to be used as a sacrificial electron donor for photochemical (λ > 400 nm) hydrogen production. In a heterogeneous mixture containing Ru(bipy) 3 2+, methyl viologen, a colloidal Pt-catalyst, and benzoylisothiocyanate 16% of 6 mmol/l benzoylisothiocyanate were oxidised after 1 h irradiation. The other investigated compounds did not function as electron donors in this system. Furthermore, ethanol was photochemically oxidised to acetaldehyde with simultaneous production of hydrogen. The obtained acetaldehyde is relatively stable with regards to further photochemical (λ > 400 nm) oxidation, <2% was further oxidised. The ratio of ethanol oxidation is dependent on catalyst concentration.