Solid-Solution-Like o-C3N4/Ag2SO4 Nanocomposite as a Direct Z-Scheme Photocatalytic System for Photosynthesis of Active Oxygen Species

Abstract

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 pr...