Constructing electrostatic self-assembled ultrathin porous red 2D g-CN/FeN Schottky catalyst for high-efficiency tetracycline removal in photo-Fenton-like processes.

The traditional heterogeneous photo-Fenton reaction was mainly restricted by the fewer surface-active sites, low Fe/Fe transformation and HO activation efficiency of catalyst. This work designed and fabricated the efficient photo-Fenton Schottky catalysts via a facile electrostatic self-assembly of metallic FeN nanoparticles scattering on the surface of red g-CN (ultrathin porous oxygen-doped 2D g-CN nanosheets). The porous morphology and exceptional electrical structure of red g-CN endowed more active sites and facilitated the photoexcited charge separation. Benefitting from the Schottky effect and unique dimensional coupling structure, the strong visible light absorption and fast spatial charge transfer were realized in the Schottky junction system. More strikingly, FeN as an efficient co-catalyst was in favor of the trap and export of e, leading to the Fe/Fe transformation and HO activation during the photo-Fenton process. Accordingly, the as-prepared catalysts revealed outstanding activity in photo-Fenton like degradation of tetracycline (TC) although under 5 W white LED light irradiation. Furthermore, the reasonable degradation pathway of TC and corresponding toxicity of the intermediates, as well as the photo-Fenton catalytic mechanism were interpreted and discussed in detail. This study would be a great aid in the development of various Schottky catalysts for heterogeneous photo-Fenton-based environmental remediation systems.