Overall water splitting under visible light irradiation over Ir and La-codoped NaTaO3 photocatalysts

Ir and La-codoped NaTaO3 has been found to be a novel photocatalyst for overall water splitting into H(2)( )and O-2 under visible light irradiation through systematic investigation in terms of doping amounts. The band structure of the sample depends on the doping amounts. Overall water splitting under visible light irradiation proceeds over Ir and La-codoped NaTaO3 with low doping levels (0.05 at% or 0.1 at% Ir to Ta) through electron transitions from the donor impurity levels formed by Ir3+ to the conduction band of NaTaO3, responding to visible light up to 500 nm. In contrast, Ir and La-codoped NaTaO3 with higher doping levels (0.5 at% or 1 at% Ir to Ta) shows photocatalytic activity not for overall water splitting but for sacrificial H2 evolution, responding to visible light beyond 600 nm.