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.