Light to H₂O₂ : The nanosheet photocatalysts containing double defects were prepared by the calcination method. The microstructure, photoelectric properties, and photocatalytic performance of the materials were systematically investigated. The −C≡N groups promote the adsorption of H⁺ and the S-defects provide the active center for the adsorption and activation of O₂.

Abstract

In this work, the graphitic carbon nitride with −C≡N defects and S-defects (N₂−SCN-4) was constructed. The H₂O₂ production efficiency of N₂−SCN-4 was 1423.3 μmol g⁻¹ h⁻¹ under the visible light (λ≥420 nm) irradiation, which was 15.4 times that of pristine g-C₃N₄. The −C≡N groups promote the adsorption of H⁺ and the S-defects provide the active center for the adsorption and activation of O₂. Furthermore, the surface morphology, microstructure, and photoelectric chemical properties of samples were investigated by a series of characterizations, and the response range of N₂−SCN-4 to visible light increases obviously. Meanwhile, the efficiency of photo-produced charge separation and the selectivity of H₂O₂ production were discussed in detail. The experimental and characterization results confirmed that the charge separation efficiency and the selectivity of the 2e⁻ O₂ reduction reaction (ORR) were improved under the synergistic effect of the double defects. This work provides a strategy for improving the photocatalytic performance of photocatalysts.