Combinatorial discovery of anomalous substrate effect on the photochemical properties of transition metal-doped epitaxial SrTiO3 heterostructures

Epitaxial Sr(VxCryTi1 x y)O3 (0 x þ y 0:05) ternary composition spreads were grown on two different single crystal substrates, LaAlO3 and Nb-doped SrTiO3, by use of combinatorial laser molecular beam epitaxy with a specially patterned slide masking plate. The photocatalytic activity on the composition spreads was evaluated by the photo-reduction of Ag+ in an AgNO3 aqueous solution to deposit Ag metal on the spreads. The V-doping effect was found to depend greatly on the substrate: the photodeposition of Ag was much enhanced in the composition region of SrV0.05Ti0.95O3 only on the Nb-doped SrTiO3, but not on the LaAlO3 and non-doped SrTiO3.