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.