Light Induced Hydrogen Production From Ethanolic Aqueous Solutions Sensitizzed By 2,4-Dimetboxy Benzylidene-2- Hydroxy Aniline And Some of Its Metal Complexes

Abstract

Hydrogen   productions  were  achieved    by  irradiating  ethanol ic aqueous solutions (20%. v/v) containing  mixtures of  the  ligand  2,4- dimethoxybcnzylidene-2-hydroxy    aniline     (HL)     or    one    of     i ts complexes  (ML2)   wi th  the  following  divalent  ions:  fVbl  (II),  Fc(IT), Co(II). Ni( rt ), Cu(H) and  Zn (11), as photosensi1izers, methyl  viol ogen (MY.:-)    as   electron   acceptor.  ethylene    diamine  tetraacctic   acid disodium   saJt (EDTA) as a sacrificial electron  donor. in  presence  of platinum  poly  (viny l   akohol) (Pt-PVA) or platinized  li02  (Pt/Ti02). (200 and 45 micron) as reduction catal ysts. using white light from 250

W xenon a rc lamp at room  temperature  25±2 °C. Oxidation Potentials

of  the  ligand  and  its  complexes were  determined by  cyclic vultammetry. The efficiency  of the photoreduction of  lv1V2+ and hydrogen production   .by  HL  and   metal   .complexe.s   was   main l y dependant  on  pH , type- and  particle  size  of cata lyst, as  well  as meLal ion  in  case  of  ML2.  Best  pertormances  were  recorded   by  the  free

ligand.