Visible-light-responsive homologous heterostructure of oxynitrides constructed to boost charge separation and water splitting

Constructing type II heterostructures represents a widely recognized strategy for enhancing charge separation and photocatalytic efficiency, but it remains challenging to fabricate homologous heterostructures based on visible-light-responsive semiconductors, especially for popularly investigated (oxy)nitrides with low thermal stability. Here, we synthesized a homologous heterostructure (denoted as YTON_H) based on the oxynitrides of YTaO_4−xN_y and YTaON₂. This heterostructure exhibits type II band structure alignment and intimate interface achieved through a magnesium (Mg) powder-assisted nitridation method. Compared with widely reported heterologous heterostructures, the as-obtained YTON_H homologous heterostructure could similarly exhibit enhanced charge separation as well as photocatalytic water splitting performance with respect to its counterparts (YTaO_4−xN_y and YTaON₂). Meanwhile, detailed structural characterizations and spectroscopy analysis have been made to confirm the formation of heterostructure and promotion of spatial charge separation.