A conjugated polymeric photocatalyst with a heterostructure and visible-light response for organic pollutant removal

Abstract

The design of organic photocatalysts with visible-light-response is an important way to solve energy crisis and environmental pollution. Polypyrrole (PPy) as one of the conjugated polymers is a prospective photocatalyst material due to its excellent optical properties, easy synthesis and high environmental stability. In this work, polyacrylonitrile (PAN) and g-C₃N₄ were electrospun as a fiber membrane matrix. PPy was coated on the matrix by in situ polymerization of a pyrrole monomer using doped Fe³⁺ as an oxidant. PPy exhibited a broadband visible light absorption region and a narrow band gap which was conducive to improve visible light utilization. The separation efficiency of photogenerated e⁻–h⁺ pairs was improved by constructing a heterojunction between PPy and g-C₃N₄. The doping of Fe³⁺ as an electron scavenger further prevented the recombination of carriers. The PAN/g-C₃N₄-PPy-Fe³⁺ membrane showed highly efficient removal performance for both cationic and anionic dyes. Moreover, PAN/g-C₃N₄-PPy-Fe³⁺ exhibited excellent recyclability and stability. This work outlined an approach for designing a novel conjugated polymer based multi-component composite photocatalyst with visible light response.