InBO3 Photocatalyst with Calcite Structure for Overall Water Splitting

Indium borate (InBO3) with a calcite structure that was prepared by a solid-state reaction and a two-step precipitation method was employed as a photocatalyst for water splitting under UV light irradiation. The InBO3 photocatalyst prepared by the precipitation method showed higher activity than that prepared by the solid-state reaction when a NiO cocatalyst was loaded on the photocatalyst. In the case of the precipitation method, the photocatalytic activity over NiO/InBO3 strongly depended on the calcination temperature and an excess amount of boric acid in the preparation. The correlation among preparation conditions, physical properties, and photocatalytic activities for water splitting has revealed that crystallinity and particle size mainly contributed to the increase in the photocatalytic activity.