A dual polymer composite of poly(3-hexylthiophene) and poly(3,4-ethylenedioxythiophene) hybrid surface heterojunction with g-CN for enhanced photocatalytic hydrogen evolution.

A surface heterojunction catalyst of g-CN-PEDOT/P3HT with P3HT and PEDOT as the polymer sensitizer and hole transport pathway is successfully prepared. The as constructed g-CN-PEDOT/P3HT composite exhibits a photocatalyst H evolution rate up to 427703.3 μmol h g which is 1059 times higher than that of g-CN, 118 times higher than that of g-CN-PEDOT with ascorbic acid as sacrificial reagents. What's more, the g-CN-PEDOT/P3HT can even show an obviously enhanced photocatalytic H evolution rate which is 6.1 times higher than that of pure g-CN in pure water without any sacrificial reagent. Combining the experimental results and molecular dynamic (MD) simulation results, a possible mechanism can be drawn that the existed PEDOT possesses relatively higher hole mobility and can be used as a hole conductor between g-CN and P3HT. Then, the photogenerated holes migration can be accelerated by PEDOT from the VB of g-CN to the VB of P3HT. All those factors may benefit the synergy among g-CN, PEDOT and P3HT, which finally facilitates the rapid migration of photoinduced electron-hole pairs and eventually improves the photocatalytic H activity process of g-CN-PEDOT/P3HT with visible light. The present work may provide useful insights for designing a surface heterojunction composite photocatalyst with high photocatalytic activity for H production.