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

As a superstar semiconducting polymer, poly(3-hexylthiophene) (P3HT) exhibits strong carrier transport ability and wide absorption range. However, pristine P3HT has almost no photocatalytic activity due to the 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 is facilitated to effective separation of the electron-hole pairs, leading to a significantly enhanced photocatalytic hydrogen evolution rate of 7327 μmol/(h·g) for the PTCN fiber membranes. This value is 57.7 times and 6.8 times more than that of P3HT fibers and powder g-C3N4, respectively. The high photocatalytic hydrogen production activity of P3HT/g-C3N4fiber membrane expands the application of P3HT. More importantly, these results indicate that the construction of heterojunction fiber materials is one of the effective strategies to enhance the photocatalytic ability of conjugated semiconducting polymers.