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-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 μmol h–1 under the irradiation of visible light (λ > 420 nm), which was about 4.5 times than that of pristine g-C3N4 (16 μmol h–1). The enhancement of photocatalytic H2 evolution is reasonably attributed to the markedly enhanced light harvesting, broadened spectral response range and low onset potential of H2 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.