Dopamine Modified g-C3N4 and Its Enhanced Visible-Light Photocatalytic H2-Production Activity

Photocatalytic water splitting is a promising strategy to convert solar energy into chemical energy. Herein, a series of g-C 3 N 4 /polydopamine (g-C 3 N 4 /PDA) composites were successfully fabricated by in situ polymerization of dopamine on the g-C 3 N 4 surface. Among all the as-prepared composites, the best photocatalytic hydrogen evolution rate of the as-prepared composites was up to 69 μmol h –1 under the irradiation of visible light (λ > 420 nm), which was about 4.5 times than that of pristine g-C 3 N 4 (16 μmol h –1 ). The enhancement of photocatalytic H 2 evolution is reasonably attributed to the markedly enhanced light harvesting, broadened spectral response range and low onset potential of H 2 production, as well as effective separation and rapid transportation of photogenerated charge carriers. More importantly, the surface modification of g-C 3 N 4 by a small amount of PDA can effectively inhibit the overgrowth of Pt nanoparticles (NPs) during the photocatalytic reactions, which promotes the photoelectron injection and better photocatalytic activity. This work should provide a new insight into preparing metal-free polymer–polymer composites with effective solar energy conversion.