Ferroelectric enhanced Z-scheme P-doped g-C3N4/PANI/BaTiO3 ternary heterojunction with boosted visible-light photocatalytic water splitting

Abstract

Utilizing surface polarization to improve the separation efficiency of photoinduced carriers is considered to be an effective strategy to enhance the photocatalytic activity. Herein, a novel nonprecious metal-based P-doped g-C₃N₄ (PCN)/polyaniline (PANI)/BaTiO₃ (BTO) (PPB) ternary photocatalyst with a hollow architecture was rationally designed and prepared by a combined wet-chemical and thermal treatment strategy. Except for the Z-scheme involved in PCN and PANI, the vertical polarization provided by ferroelectric BTO further improved the separation efficiency of the photoinduced charge carrier, resulting in an enhanced visible-light photocatalytic hydrogen production activity of 602 μmol h⁻¹ g⁻¹, which was 21-fold higher than that of pristine g-C₃N₄, and an apparent quantum efficiency of 4.16% at 420 nm. In addition, benefitting from this ternary heterojunction, the photoinduced electrons were concentrated on the intermediate p-type PANI while holes were left on the lateral n-type PCN involved in the Z-scheme, resulting in the retention of high oxidation–reduction potentials. Moreover, this approach to enhance the photocatalytic activity by constructing a Z-scheme heterojunction and surface polarization could expand to other photosystems, which provides a new avenue for the rational design and the synthesis of novel photocatalysts.