Design of a two-dimensional interplanar heterojunction for catalytic cancer therapy

Limited substrates content is a major hurdle dampening the antitumor effect of catalytic therapy. Herein, a two-dimensional interplanar heterojunction (FeOCl/FeOOH NSs) with ·OH generation under ultrasound irradiation is fabricated and utilized for catalytic cancer therapy. This interplanar heterojunction is prepared through replacing chlorine from iron oxychloride with hydroxyl. Benefiting from the longer hydroxyl bond length and enhanced affinity with water, the alkali replacement treatment integrates interplanar heterojunction synthesis and exfoliation in one step. In particular, a build-in electric field facilitated Z-scheme interplanar heterojunction is formed due to the aligning Fermi levels. The holes on the valence band of FeOCl have great ability to catalyze O₂ evolution from H₂O, meanwhile, the generated O₂ is immediately and directly reduced to H₂O₂ by the electrons on the conductive band of FeOOH. The self-supplying H₂O₂ ability guarantees efficient ·OH generation via the Fenton-like reaction catalyzed by FeOCl/FeOOH NSs, which exhibits excellent anti-tumor performance.