Double-Shelled Porous g-C 3 N 4 Nanotubes Modified with Amorphous Cu-Doped FeOOH Nanoclusters as 0D/3D Non-Homogeneous Photo-Fenton Catalysts for Effective Removal of Organic Dyes.

Graphite phased carbon nitride (g-C 3 N 4 ) has attracted extensive attention attributed to its non-toxic nature, remarkable physical-chemical stability, and visible light response properties. Nevertheless, the pristine g-C 3 N 4 suffers from the rapid photogenerated carrier recombination and unfavorable specific surface area, which greatly limit its catalytic performance. Herein, 0D/3D Cu-FeOOH/TCN composites are constructed as photo-Fenton catalysts by assembling amorphous Cu-FeOOH clusters on 3D double-shelled porous tubular g-C 3 N 4 (TCN) fabricated through one-step calcination. Combined density functional theory (DFT) calculations, the synergistic effect between Cu and Fe species could facilitate the adsorption and activation of H 2 O 2 , and the separation and transfer of photogenerated charges effectively. Thus, Cu-FeOOH/TCN composites acquire a high removal efficiency of 97.8%, the mineralization rate of 85.5% and a first-order rate constant k = 0.0507 min -1 for methyl orange (MO) (40 mg L -1 ) in photo-Fenton reaction system, which is nearly 10 times and 21 times higher than those of FeOOH/TCN (k = 0.0047 min -1 ) and TCN (k = 0.0024 min -1 ), respectively, indicating its universal applicability and desirable cyclic stability. Overall, this work furnishes a novel strategy for developing heterogeneous photo-Fenton catalysts based on g-C 3 N 4 nanotubes for practical wastewater treatment.