Dopamine Modified g-C3N4 and Its Enhanced Visible-Light Photocatalytic H-2-Production Activity

Photocatalytic water splitting is a promising strategy to convert solar energy into chemical energy. Herein, a series of g-C3N4/polydopamine (g-C3N4/PDA) composites were successfully fabricated by in situ polymerization of dopamine on the g-C3N4 surface. Among all the as-prepared composites, the best photocatalytic hydrogen evolution rate of the as-prepared composites was up to 69 mu mol h(-1) under the irradiation of visible light (lambda > 420 nm), which was about 4.5 times than that of pristine g-C3N4 (16 mu mol 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-C3N4 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.