Controlled synthesis of CaTiO3:Ln3+ nanocrystals for luminescence and photocatalytic hydrogen production

Abstract

Bifunctional CaTiO₃:Ln³⁺ (Ln = Eu and Er) nanocrystals were prepared via a facile method followed by calcination in air. The as-prepared CaTiO₃:Ln³⁺ nanocrystals exhibited bifunctional performance for both photoluminescence and photocatalytic hydrogen production. As a phosphor powder, the luminescence properties of CaTiO₃:Ln³⁺ nanocrystals could be controlled by doping with different Ln³⁺ ions. They showed very stable luminescence properties and a much higher quenching concentration due to the scheelite related structure of CaTiO₃, which was up to 17% (Eu doping). As a photocatalyst, the CaTiO₃:Ln³⁺ nanocrystals exhibited a higher activity for hydrogen production under ultraviolet light irradiation. The CaTiO₃:Er³⁺ nanocrystals displayed the highest photocatalytic activity of up to 461.25 μmol h⁻¹, which was higher than that of CaTiO₃:Eu³⁺ nanocrystals and pure CaTiO₃. The results indicated that incorporation of Ln³⁺ ions benefits electron transfer as well as the reduction of the band gap of the CaTiO₃ photocatalyst.