When C3N4 meets BaTiO3: Ferroelectric polarization plays a critical role in building a better photocatalyst

Photogenerated electrons (e(-)) and holes (h(+)) easily undergo fast recombination in many semiconductors, limiting the further improvement of its photocatalytic efficiency. To solve this bottleneck problem, graphitic C3N4 was used to group tetragonal-phase BaTiO3 ferroelectric and successfully constructed the g-C3N4/BaTiO3 heterojunction via a facial mixing-calcination method. These composites exhibited an extraordinary improvement under visible-light irradiation, achieving a 1 + 1 > 2 performance compared with their single pristine components. It is because the formation of double-transfer structure promotes the fast transfer of photo-induced charge carriers in g-C3N4/BaTiO3 composites. Synergy between the two materials, especially the ferroelectric polarization, plays a key role in facilitating the spatial separation of photo-excited e(-)/h(+) pairs and improving the photocatalytic efficiency.