A Multifunctional MoS2/g-C3N5 2D Heterointerface for Solar-Driven Ciprofloxacin Degradation, Oxygen Reduction, Oxygen Evolution Electrocatalysis, and Fluorescent Glyphosate Sensing

Abstract

Developing multifunctional heterostructures capable of integrating environmental remediation, solar-to-chemical conversion, electrocatalysis, and chemical sensing within a unified material platform remains a major challenge due to the lack of a common structure–property relationship governing these diverse functionalities. Herein, a 2D/2D MoS2/g-C3N5 heterostructure was rationally engineered via a facile ultrasonic-assisted assembly strategy to construct an electronically coupled heterointerface with accelerated interfacial charge transfer kinetics. Structural, morphological, optical, and electrochemical investigations collectively confirm the intimate integration of MoS2 nanosheets with the g-C3N5 framework, resulting in enhanced visible light absorption, suppressed charge recombination, directional migration, and surface electronic modulation. Importantly, these interfacial electronic features serve as the common mechanistic origin for observed multifunctional behavior. The optimized MC31 (MoS2/g-C3N5 = 3:1) heterostructure exhibits superior solar-light-driven ciprofloxacin (CIP) degradation, predominantly mediated by superoxide (•O2–) radicals, along with enhanced photocatalytic H2O2 generation. The same charge-separation characteristics further promote efficient oxygen evolution electrocatalysis by facilitating rapid interfacial electron transport and favorable surface reaction kinetics. In parallel, the electronically modulated heterointerface enables sensitive fluorescence-based glyphosate sensing through effective charge-transfer-induced fluorescence quenching. Mechanistic investigations suggest that the enhanced multifunctional performance originates from a direct Z-scheme charge transfer pathway established across the MoS2/g-C3N5 interface, which simultaneously preserves strong redox potentials and accelerates spatial carrier separation. This work establishes interfacial electronic engineering as a unifying strategy for designing multifunctional 2D heterostructures capable of coupling photocatalytic, electrocatalytic, and sensing functionalities within a single material platform.