Homogeneously Nitrogen Doped BaLa4Ti4O15Extending Visible Light Responsive Range for Photocatalytic Oxygen Evolution

Abstract

Homogeneous nitrogen doping is a promising strategy for narrowing the band gap of layered metal oxides without altering the crystal structures and microstructures of precursors. In this work, BaLa4Ti4O15, a (111) plane-type layered perovskite metal oxide with a band gap of about 3.77 eV, was doped with nitrogen by a thermal treatment in an ammonia atmosphere. The nitrogen dopants are homogeneously distributed in the layered perovskite framework, resulting in an extended band-to-band visible light absorption edge up to 600 nm, corresponding to a band gap of 2.07 eV. It is worth noting that the nitrogen doping process has trivial impact on the crystal structure, microstructure, and chemical states of the BaLa4Ti4O15, which minimizes the side effect of photogenerated carrier separation and surface chemical reaction. BaLa4Ti4O15–xNy exhibited efficient photocatalytic water oxidation activity under visible light. This work highlights the usefulness of homogeneous doping for tuning wide band gap layered metal oxides.