Photocatalytic reduction for graphene oxide by PbTiO3 with high polarizability and its electrocatalytic application in pyrrole detection

Quick recombination of photogenerated electrons and holes in photocatalytic process remains a huge challenge. And the routine efforts are concentrated on heterojunction , metal decoration and surface defect strategies. PbTiO 3 as a typical perovskite ferroelectrics is with a strong built-in   electric field as self-junction caused by internal spontaneous polarization, facilitating the charge separation in the photocatalytic process. Here, under UV irradiation , L-shaped PbTiO 3 with active (1 1 0) facet as a photocatalyst was applied to photo-reduce graphene oxide (GO), where a specific reduced graphene oxide (rGO)/PbTiO 3 composite was synthesized in presence of isopropanol, a hole-trapping agent. According to the linear optical properties , the polarizability of PbTiO 3 is calculated to 1.01 × 10 −23  cm 3 (2.68 times that of P25 (TiO 2 )), inducing the photo-excited charge separation by PbTiO 3 . Based on XPS characterization, a Ti O C chemical bond is identified on the interface between rGO and PbTiO 3 . The response peak current for an electrochemical sensor based on rGO/PbTiO 3 was proportional to the concentration of pyrrole (6.6 × 10 −9 –3.1 × 10 −7 M, R 2  = 0.999), and an extremely low limit reaches to 2.38 × 10 −9 M. In addition, polypyrrole during the pyrrole detection was realized by the multi-cycle oxidation process . And also, the electrochemical detection has been successfully applied for the pyrrole quantification in real samples.