Hydrogen generation from photocatalytic treatment of wastewater containing pharmaceuticals and personal care products by Oxygen-doped crystalline carbon nitride

• Oxygen-doped crystalline carbon nitride (CCNO) was successfully synthesized. • Pharmaceuticals and personal care products (PPCPs) were readily degraded by CCNO. • Hydrogen fuel was recovered from photocatalytic degradation of PPCPs by CCNO. • An energy-recovering wastewater treatment process using solar energy is proposed. Degrading organic pollutants while generating hydrogen from water splitting is an ideal application of photocatalysis. Herein, we presented an efficient photocatalyst, oxygen-doped crystalline carbon nitride, to power the degradation of various kinds of pharmaceuticals and personal care products and the simultaneous hydrogen production. The highest efficiency was achieved in treating the simulated wastewater containing naproxen (NPX), with the H 2 evolution rate of 819.1 µmol/g/h and the NPX degradation efficiency of 92 % upon visible light irradiation. Experimental and computational results suggested that the doped oxygen atoms thermodynamically favored the generation of hydroxyl peroxide for pollutant degradation and lowered the energy barrier of H 2 O reduction to produce hydrogen fuel. Most importantly, the catalysts functioned well in the natural aquatic environment including sea water, sewage water, river water, and well water. This study provides fundamental insights into photocatalytic water treatment with simultaneous hydrogen production, indicating an energy-recovering approach for wastewater treatment.