P3HT/g-C3N4 composite fiber membranes for high-performance photocatalytic hydrogen evolution

Abstract

As a superstar semiconducting polymer, poly(3-hexylthiophene) (P3HT) demonstrates high efficiency in carrier transport ability and wide absorption range. However, pristine P3HT exhibits minimal photocatalytic activity as a result of its short carrier transport distance and fast electron-hole recombination. Here, we strategically fabricated P3HT/g-C3N4 composites on polymethyl methacrylate (PMMA) fiber (PTCN) via electrospinning and the physicochemical properties were fully investigated. Raman spectroscopy, ultraviolet–visible (UV–Vis) absorption spectra and X-ray photoelectron spectroscopy (XPS) results demonstrated a well-defined p-n heterojunctions can be formed between P3HT and g-C3N4 molecules through π-π interaction and extended conjugated length of P3HT could be achieved by tuning the ratios of P3HT relative to g-C3N4. The presence of the heterojunctions facilitates the effective disconnection of the electron-hole pairs, resulting in a significantly enhanced photocatalytic hydrogen evolution rate of 7327 μ mol/(h·g) for the PTCN fiber membranes. This value exceeds that of P3HT fibers by 57.7 times and powder g-C3N4 by 6.8 times, respectively. The high photocatalytic hydrogen production activity of P3HT/g-C3N4 fiber membrane expands the application of P3HT. More importantly, these results indicate that the construction of heterojunction fiber materials is a promising approach for improving the photocatalytic ability of conjugated semiconducting polymers.