A novel ternary Mn2O3 decorated GO-MoS2 heterostructure for enhanced tetracycline degradation and green H2 production under visible light

Abstract

In this work, the facile synthesis of a manganese(III) oxide decorated on graphene oxide molybdenum disulphide composite (Mn₂O₃@GO-MoS₂) is reported as a sustainable photocatalyst for the production of green hydrogen (H₂) and the degradation of tetracycline (TC). Detailed characterization of the Mn₂O₃@GO-MoS₂ composite revealed its tailored optical bandgap, crystal structure and enhanced separation efficiency. The results showed that 98.85% degradation of TC was attained within 15 minutes. This high degradation performance was attributed to the increased TC adsorption onto the Mn₂O₃@GO-MoS₂ composite surface, the low bandgap energy, the low recombination rate, and the relocation of light absorption into the visible range. The H₂ production rate using Mn₂O₃@GO-MoS₂ composite was 14.55 mmol g⁻¹ h⁻¹. The pronounced visible light absorption through a tunable band gap (1.34 eV) and the low electron–hole (e⁻/h⁺) pairs recombination are the primary causes of the observed catalytic activity. The primary reactive species responsible for TC degradation are h⁺ and ˙O₂⁻. The high-resolution mass spectroscopy (HRMS) analysis predicts key intermediates and the degradation pathway. A minor reduction of 9.5% in TC degradation efficiency after five successful cycles indicates that the composite is stable and reproducible. The crucial advantages of the Mn₂O₃@GO-MoS₂ composite are that it can be easily recovered from the solution and exhibits phenomenal reusability, with six cycles of H₂ production. This work presents a straightforward, economical, and eco-friendly method for fabricating highly reusable Mn₂O₃@GO-MoS₂ composite aimed at treating TC and producing green H₂.