Z-scheme-type conductive-polymer-P3HT/KTa(Zr)O3 heterojunction composites for enhancing the photocatalytic activity of water splitting

[Display omitted] •P3HT-coated KTa(Zr)O3 photocatalyst work complete photocatalytic water splitting, and enhanced the photocatalytic activity.•An interface between P3HT- KTa(Zr)O3 was formed and efficient charge transfer was performed at the interface.•The action spectrum suggests this catalyst was a Z-scheme type reaction that widely utilizes ultraviolet light to visible light.•The complete water splitting activity can be increased by combining P3HT by Z-scheme type photocatalytic reaction. Photocatalytic water splitting on Pt/KTa(Zr)O3 modified with poly(3-hexylthiophene-2,5-diyl) (P3HT) as a photoconductive organic polymer is investigated. The photocatalyst powder of Pt/P3HT/KTa(Zr)O3 was synthesized by evaporation to dryness method. The H2/O2 production ratio of the unmodified catalyst was 2.90, whereas the H2/O2 production ratio become close to 2 (1.66–2.26) with loading P3HT (0.1 wt% to 0.8 wt%). The optimum amount of P3HT added was 0.4 wt% and the H2/O2 production ratio was 2.00, which increased the hydrogen production rate by 476 % compared to the unmodified photocatalyst. As a result of the fluorescence lifetime measurement, when the dye and platinum were supported on KTa(Zr)O3, charge separation into the dye and platinum was confirmed in both UV and visible light irradiation. Irradiation with visible light in addition to UV light increased the water splitting activity, while water decomposition was not performed only with visible light, suggests Z-scheme type water splitting reaction.