Photocatalytic hydrogen production in the water/methanol system using Pt/RE:NaTaO3 (RE = Y, La, Ce, Yb) catalysts

Perovskite type RE-doped NaTaO3 (where RE represents Rare Earths elements like Y, La, Ce, Yb) catalysts, derived from solid state synthesis method, have been used for the photocatalytic hydrogen production from water using methanol as sacrificial agent. The photocatalytic activity of NaTaO3 in H2 production is improved on its doping with Y, La or Yb elements. In contrast, Ce-doped sample shows a worsening of the photoactivity, which is even lower than the un-doped catalyst. The characterization of the materials reveals that the monoclinic structure and the presence of Ce4+ do not favour to increase the performance of NaTaO3. Previous reports proved that La-doping boosted the water splitting photoactivity of NaTaO3. However the results of this work reveal an increase in the H2 production by the use of Y as dopant. This enhancement in the photoactivity could be related with the modification of the opto-electronic properties of NaTaO3 with the inclusion of RE elements (Y, La, Yb) in the orthorhombic structure of this perovskite. Moreover, the catalytic activity of all the RE-doped samples is further increased on their modification with Pt nanoparticles (NPs) loading that act as photo-generated electron scavenger facilitating the reduction reactions.