Direct injection of electrons into Cu active sites from porous phosphorus-doped g-C3N4 for enhanced Fenton-like performance.

[Display omitted] • A CuO x catalyst supported on P-doped porous g-C 3 N 4 is synthesized easily. • P-doping increases the number of unpaired electrons in the catalyst. • Porous defects increase the catalyst surface area and active sites. • The unpaired electrons in the catalyst can directly inject into Cu active sites. • Catalyst performance and H 2 O 2 utilization efficiency are simultaneously improved. Copper oxides were supported on porous P-doped g-C 3 N 4 (Cu/p-PCN) by a stepwise calcination process. Elemental analysis, XPS, and ESR results show that P atoms enter the network of g-C 3 N 4 , and the thus-fabricated configuration could provide additional electrons for the conjugated system of g-C 3 N 4. As verified by TEM, XRD, XPS, and FTIR results, copper is mainly present as oxides on the catalyst surface and undergoes Cu-π interactions with porous P-doped g-C 3 N 4 (p-PCN). During the reaction, unpaired electrons in p-PCN can be injected into the Cu active sites, prompting the decomposition of H 2 O 2 into hydroxyl radicals (•OH). The degradation begins with the activation of H 2 O 2 into •OH radicals by the Cu(I) active center. The depleted Cu(I) centers are then regenerated by electron injection from P atoms rather than by the reaction between H 2 O 2 and Cu(I). Thus, the catalyst performance and H 2 O 2 utilization are greatly enhanced. Equally significantly, the porous structure of Cu/p-PCN also contributes appreciably to its performance by increasing the specific surface area and active sites. Cu/p-PCN exhibits better performance than many reported catalysts in similar conditions, robust resistance to interference from various ions, high degradation efficiency over a wide pH range, and excellent degradation ability for various pollutants. [ABSTRACT FROM AUTHOR]