Visible light driven hydrogen peroxide production by oxygen and phosphorus co-doped CoP-C₃N₄ photocatalyst

Photocatalytic hydrogen peroxide (H₂O₂) by oxygen and phosphorus co-doped graphitic carbon nitride (C₃N₄) with cobalt phosphate (CoP) cocatalyst is investigated. The photocatalyst powder of CoP-C₃N₄ 1:n, n = 0–4, n is the weight ratio of cyanuric acid added) was synthesized by melamine cyanurate template method. Characterization of the catalyst was performed by X-ray diffraction analysis, and scanning electron microscopy, X-ray photoemission spectra, and fluorescence decay spectra. Oxygen doping was performed by the melamine and cyanuric acid template method, followed by phosphorus doping of the C₃N₄ backbone by the introduction of CoP. Co-doping of O and P atom facilitated charge transfer on the C₃N₄ backbone, while CoP facilitated charge separation at the C₃N₄ interface. The CoP-C₃N₄ (1:4) photocatalyst increased H₂O₂ production rate by 293 % compared to that of the cyanuric acid-free photocatalyst and also achieved the photocatalytic oxygen evolution from water. These results indicate that O,P co-doped CoP-C₃N₄ can perform sacrificial agent-free hydrogen peroxide under visible light irradiation.