Porous g-C3N4 and α-FeOOH bridged by carbon dots as synergetic visible-light-driven photo-fenton catalysts for contaminated water remediation

Merging photocatalysis with Fenton-like reaction provides a promising synergetic advanced oxidation technology for water treatment, whereas the rational design of efficient cooperative photo-Fenton system still remains a great challenge. In this study, a ternary α-FeOOH/carbon dots/porous g-C3N4 (α-FeOOH/CDs/p-GCN) composite is developed as visible-light-driven heterogeneous photo-Fenton catalyst for contaminated water remediation. α-FeOOH nanorods are in-situ grown on porous g-C3N4 substrates, among which CDs are intercalated as high-speed electron transmission bridges, simultaneously preventing the photogenerated electron-hole recombination and accelerating the Fe3+/Fe2+ redox cycle. The distinctive heterostructure and synergetic catalytic effect endow α-FeOOH/CDs/p-GCN with superior efficiency, reusability, and universality for recalcitrant pollutant elimination, the reaction rate of which is nearly 13.6, 7.3, 3.4, 1.4, and 5.1 times higher than that of α-FeOOH, bulk g-C3N4 (b-GCN), p-GCN, α-FeOOH/p-GCN, and α-FeOOH/CDs/b-GCN, respectively. The FeOOH/CDs/p-GCN also demonstrates excellent tolerance to realistic environmental matrices including deionized water, sea water, river water, wastewater, and underground water. HO• and •O2− radicals are proved to be the predominant contributors in the photo-Fenton system. This work provides an efficient synergetic visible-light-driven photo-Fenton catalyst possessing great potential for practical contaminated water remediation. [Display omitted] •A ternary α-FeOOH/carbon dots/porous g-C3N4 composite was developed.•The porous g-C3N4 facilitates visible light harvesting and mass transfer.•CDs serve as high-speed electron transmission bridges between interfaces.•Prevent photogenerated e−-h+ recombination and accelerate Fe3+/Fe2+ redox cycle.•The composite exhibits superior activity, excellent stability and generality.