In Situ 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 HMoxNb3–xO8 nanosheets, was fabricated via in situ 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/HMoxNb3–xO8 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 in situ construction of high-performance 2D/2D heterojunction photocatalysts for environmental remediation.