Novel Cu-Fe bi-metal oxide quantum dots coupled g-C3N4 nanosheets with H2O2 adsorption-activation trade-off for efficient photo-Fenton catalysis

Exploitation of catalysts with multi-active sites is very important for enhancing catalytic performance. 0D/2D hybrids, especially quantum dots (QDs)/nanosheets (NSs), have attracted increasing attentions for advanced oxidation processes due to high charge mobility and more active sites. However, 0D/2D hybrids with multi-active sites still remain a great challenge. Herein, 0D Cu-Fe bi-metal oxide QDs/2D g-C3N4 (CNNSs) exhibiting superior advantages beyond single-metal 0D/2D counterparts was fabricated via a facile one-step synthesis strategy for photo-Fenton catalysis. The synergy of ultrafine Cu-Fe sites on CNNSs led to outstanding tetracycline removal efficiency over a wide pH range. Our experiments and DFT calculations clearly demonstrated that except for the fast charge separation and transfer, this synergy could achieve the optimal H2O2 adsorption-activation trade-off on Cu-Fe sites, while also modify tetracycline absorption, leading to multiple synergies of adsorption-catalytic degradation and photocatalysis-Fenton oxidation. This work provides new insights in developing multi-functional 0D/2D hybrids for environment and energy applications.