Growth mechanism of 2D heterostructures of polypyrrole grown on TiO 2 nanoribbons for high-performance supercapacitors.

The patterning of functional structures is crucial in the field of materials science. Despite the enticing nature of two-dimensional surfaces, the task of directly modeling them with regular structures remains a significant challenge. Here we present a novel method to pattern a two-dimensional polymer in a controlled way assisted by chemical polymerization, which is confirmed through discernible observation. The fabrication process involves in situ polymerization to create 2D layers of polypyrrole (PPy) on extended 2D TiO 2 nanoribbons, resulting in oriented arrays known as 2D PPy/TiO 2 . These arrays exhibit enhanced electrochemical performance, making them ideal for supercapacitor applications. The skeleton structure of this material is distinctive, characterized by a homogeneous distribution of layers containing various elements. Additionally, it possesses a large contact surface, which effectively reduces the distance for ion transport and electron transfer. The 2D PPy/TiO 2 electrode has a maximum specific capacitance of 280 F g -1 at an applied current density of 0.5 A g -1 . Moreover, it demonstrates excellent rate capability and cycling stability. Therefore, this approach will open an avenue for improving polymerization-based patterning toward recommended applications.