High visible light photocatalytic activities obtained by integrating g-C3N4 with ferroelectric PbTiO3

Abstract

Graphitic carbon nitride (g-C3N4) with the merits of high visible light absorption, proper electronic band structure with high conduction band edge and variable modulation, is viewed as a promising photocatalyst for practical use. To alleviate its high recombination rate of photo-excited charge carriers and maximize the photocatalytic performances, it is paramount to design highly effective transfer channels for photo-excited charge carriers. Ferroelectric materials can have the charge carriers transport in opposite directions owing to the internal spontaneous polarization, which may be suitable for constructing the heterostructure with g-C3N4 for efficient charge separation. Inspired by this concept, herein ferroelectric PbTiO3, which can be the visible-light absorber, is coupled with g-C3N4 to construct PbTiO3/g-C3N4 heterostructure with close contact via Pb–N bond by the facile post thermal treatment. The optimized PbTiO3/g-C3N4 heterostructure exhibited excellent photocatalytic and photoelectrochemical activities under visible light irradiation. Moreover, the simultaneous application of ultrasound-induced mechanical waves can further improve its photocatalytic activities through reinforcing the built-in piezoelectric field. This work proposes a widely applicable strategy for the fabrication of high-performance ferroelectric based photocatalysts and also provides some new ideas for developing the understanding of ferroelectric photocatalysis.