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

Abstract

Ir and La-codoped NaTaO3 has been found as a novel photocatalyst for overall water splitting into H2 and O2 under visible light irradiation by systematical investigation in terms of the 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 small doping levels (0.05 at% or 0.1 at% Ir to Ta) by the electron transition 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 large 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.