Coral-like potassium and phosphorous doped graphitic carbon nitride structures with enhanced charge and mass transfer dynamics toward photocatalytic hydrogen peroxide production and microbial disinfection

Abstract

This study provided insight on the design of co-doped graphitic carbon nitride (g-C₃N₄) structures by using potassium dihydrogen phosphate (KH₂PO₄) as a promising material for the supply of potassium (K) and phosphorus (P) elements. The addition of KH₂PO₄ to the cyanuric acid-melamine complex (CM) solution stabilized its structure by coordinating potassium ions (K⁺) in the hexagonal pores and dihydrogen phosphate ions (H₂PO₄^-) in dangling bonds on the edge sites. The resultant supramolecular structure (KP-CM) with a unique skeleton governed the polycondensation process, resulting in K and P co-doped g-C₃N₄ structures with a distinct coral-like morphology (KP-CN). Employing the KP-CM complex as a precursor could modify the optoelectronic behaviour of the photocatalysts via the synergistic effect of the co-doping process. It could also be beneficial in terms of economic considerations by increasing the catalyst synthesis yield. The resulting g-C₃N₄ showed a remarkable hydrogen peroxide (H₂O₂) production rate of 216 µmol L^-1h^-1 compared to the rate of the pristine sample of 137 µmol L^-1h^-1. It also exhibited significant photocatalytic antibacterial activity in Escherichia coli (E. coli) disinfection.

Keywords: Graphitic carbon nitride; Hydrogen peroxide; Photocatalytic disinfection; Potassium-phosphorus co-doping; Supramolecular structure.