<i>In Situ</i> Engineering of Two-Dimensional Heterostructures for Enhanced Photocatalytic Decontamination of Methyl Orange

Two-dimensional (2D)/2D heterostructured catalysts have garnered significant attention in photocatalytic environmental remediation due to their relevance in optoelectronic, as well as solar energy conversion systems. However, fast photocarrier separation of 2D/2D heterojunctions, made from the stacking of different layered materials through strong chemical bonds rather than weak van der Waals interactions, remains an unmet challenge. To address this, herein, a generation of 2D/2D p-n heterojunction photocatalysts, composed of BiOCl and HMo _<i>x</i> Nb₃ _-<i>x</i> O₈ nanosheets, was fabricated via <i>in situ</i> chemical absorption and hydrolysis strategies. This close heterojunction interface enhanced the separation and migration of photoinduced electron-hole (e^--h⁺) pairs. As a result, the prepared ultrathin BiOCl/HMo _<i>x</i> Nb_3-<i>x</i> O₈ heterostructure catalysts demonstrated superior photocatalytic degradation of methyl orange (MO) under UV-visible light, with the optimized photocatalysts (BiOCl/NbMo_-10) achieving MO removal efficiencies 2.94 and 2.22 times greater than those of pristine BiOCl and NbMo_-10 materials, respectively. Further, hydroxyl radicals (·OH), positive holes (h⁺), and superoxide anions (·O₂ ^-) were also confirmed to play key roles in MO removal within the photocatalytic system. This work offers insights into the rational design and <i>in situ</i> construction of high-performance 2D/2D heterojunction photocatalysts for environmental remediation.