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Graphene-like carbon nitride supported plasmonic Au NPs with physical barrier-free interface (Au/C3N4) were in situ synthesized by one-step polymerization of the homogeneous mixture of HAuCl4 and urea. The plasmonic graphene-like structure of Au/C3N4 with the physical barrier-free interface enhances the visible-light capturing capability, increases the redox potentials, and facilitates the directional transfer of electrons from N 2p of C3–N species in g-C3N4 to Au in the photocatalytic procedure, which greatly promotes the activity of Au/C3N4 for the evolution of •O2 –, •OH, and H2O2 species. The optimal Au/C3N4 sample provides the highest photocatalytic efficiency of active oxygen species, obtaining 31 (•OH), 68 (•O2 –), and 990 μmol L–1 h–1 (H2O2) without scavenger under visible light, respectively. The work supplies a new approach to design efficient graphene-like structures with a physical barrier-free interface for photocatalytically enhancing sustainable solar conversion.

Efficient photosynthesis of active oxygen species (e.g., •OH, •O2 –, and H2O2) is of cardinal significance for environmental science and biochemistry. We report a system of o-C3N4/Ag2SO4 with solid-solution-like structure synthesized by coordinating the 5s orbit of Ag+ with surface 2p lone electrons of o-C3N4. The as-synthesized o-C3N4/Ag2SO4 demonstrates a unique electronic structure, as illuminated high light absorption, perfect redox potentials, large BET specific area, abundant active sites, and efficient interfacial charge transfer. Electron paramagnetic resonance spectra and Mott–Schottky measurements confirm that o-C3N4/Ag2SO4 photocatalysts demonstrate highly efficient activity for yielding •OH, •O2 –, and H2O2 species with the Z-scheme photocatalytic principle. Experimental and DFT calculation reveal that the transferred electrons on the conduction band (CB) made up of Ag 5s were favorably shifted into the valence band (VB) composed of N 2p with the formed coordination under irradiation, greatly promoting electron transportation in the Z-scheme photocatalytic system. (o-C3N4)2/(Ag2SO4)1 with the mass ratio of 2 to 1 possesses the highest photocatalytic rate of •OH (45 μmol L–1 h–1), •O2 – (87 μmol L–1 h–1), and H2O2 (480 μmol L–1 h–1). The work provides a new approach to design advanced photocatalysts to efficiently yield active oxygen species for environmental purification.