Enhanced photocatalytic performance of MXene-Modified cation-exchanged CoFe-LDH/CoFeCrO₄ heterostructure for Antibiotic degradation and hydrogen production through synergistic charge dynamics

Systemizing an effective charge-transfer channel across a junction interface replete with ample active sites for enhancing the photocatalytic activity of semiconducting materials presents a formidable challenge. Here, we present a novel approach based on an in situ hydrothermal method for synthesizing CoFe-Layered Double Hydroxide (LDH)/CoFeCrO₄ heterojunction materials that were partially derived from CoFe-LDH. These materials synergistically interact with Ti₃C₂ MXene nanosheets facilitating multi-interface interactions. Indeed, the highest tetracycline hydrochloride degradation rate of nearly 92% in 2 h was achieved because of the intense synergy between the CoFe-LDH/CoFeCrO₄ heterojunction material optimized with 7.5 wt% of MXene nanosheets (CMC-7.5). This degradation performance was 3.1 times greater than that of the original CoFe-LDH. Further, CMC-7.5 produces the highest H₂ gas of 458.79 μmol h⁻¹g⁻¹ from a photocatalytic water splitting reaction. The formation of a Schottky energy barrier between the partially derived CoFe-LDH/CoFeCrO₄ unit and MXene promoted the fast transfer of photogenerated electrons from CoFe-LDH/CoFeCrO₄ to the surface of MXene, thereby providing a plethora of active sites for photocatalytic reactions. Photoelectrochemical assessments using transient and linear sweep voltammetry along with electrochemical impedance spectroscopy confirmed efficient charge carrier transfer. Moreover, the optimized CMC-7.5 photoelectrode has a superior integral area and exhibited excellent stability over 100 cycles. Finally, the study outlines the construction of several advanced materials with multi-interface heterojunctions involving cation-exchanged LDH derivatives with high photogenerated charge carrier separation efficiency and minimal interfacial migration resistance to serve as stability benchmarks for practical applications.