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. PbTiO3 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 PbTiO3 with active (1 1 0) facet as a photocatalyst was applied to photo-reduce graphene oxide (GO), where a specific reduced graphene oxide (rGO)/PbTiO3 composite was synthesized in presence of isopropanol, a hole-trapping agent. According to the linear optical properties, the polarizability of PbTiO3 is calculated to 1.01 x 10(-23) cm(3) (2.68 times that of P25 (TiO2)), inducing the photo-excited charge separation by PbTiO3. Based on XPS characterization, a Ti-O-C chemical bond is identified on the interface between rGO and PbTiO3. The response peak current for an electrochemical sensor based on rGO/PbTiO3 was proportional to the concentration of pyrrole (6.6 x 10(-9)-3.1 x 10(-7) M, R-2 = 0.999), and an extremely low limit reaches to 2.38 x 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. (C) 2019 Elsevier Inc. All rights reserved.