Enhanced overall water splitting under visible light irradiation over Ir- and La-codoped NaTaO3 by post KCl flux treatment

Abstract

The effectiveness of a post treatment using alkaline chlorides on overall water splitting under visible light irradiation over Ir and La-codoped NaTaO₃ photocatalysts was investigated. The water-splitting activity tripled as a result of the KCl flux treatment. Na⁺ ions at the surface were preferably substituted with K⁺ ions compared to Rb⁺ and Cs⁺ ions, resulting in the formation of K⁺ ion-enriched surfaces regarded as KTaO₃. Such K⁺ ion-enriched surfaces function as reduction sites of water to produce H₂, contributing to an increased number of reduction sites and promoting the spatial separation of reduction and oxidation sites.