Localized photothermal effect mediated strategy of graded solar utilization in MXene-Bi2MoO6 Schottky heterojunction

Abstract

The strategy of graded solar utilization (GSU) converts long-wavelength sunlight into thermal energy, thereby enhancing reaction efficiency. In this study, GSU-driven MXene-Bi₂MoO₆ Schottky heterojunctions have been developed to improve photocatalytic degradation of norfloxacin via localized photothermal effect (LPE). LPE facilitates the accumulation of thermal energy and elevates local temperatures at the reaction site, significantly accelerating targeted reactions. Specifically, the sheet-on-sheet (2D/2D) Schottky heterostructure demonstrates a 2.53-fold enhancement in photocatalysis compared to other configurations, including pristine Ti₃C₂T_X (1.11 times), pristine Bi₂MoO₆ (1.23 times), physical mixtures (1.49 times), sheet-covered-sheet (2D@2D) morphology (1.80 times), and conventional heat effects (1.61 times). This superior performance is attributed to tighter heterojunction coupling, shorter heat transfer distances, and the localized heating effect. Additionally, degradation pathway analysis reveals that LPE reduces both molecular weight and diversity during photocatalytic processes. This work elucidates the mechanism behind LPE enhancement and achieves comprehensive utilization of the full solar spectrum in photocatalysis.