Interfacial engineering of MoS2 and bimetallic MOF hybrid for superior piezo-photocatalytic hydrogen production and wastewater treatment

A novel hybrid heterojunction composite (MoS₂@Cu/Co-MOF) was fabricated via hydrothermal method for hydrogen production via water splitting and wastewater treatment. The as-prepared MoS₂@Cu/Co-MOF heterostructure was characterised using X-ray diffraction (XRD), Transmission electron microscopy (TEM), Field emission-scanning electron microscopy (FE-SEM), Brunauer–Emmett–Teller (BET), UV-Vis Diffuse Reflectance Spectroscopy (UV–vis DRS), Electrochemical impedance spectroscopy (EIS) and Chronoamperometry (CA). The FE-SEM and TEM confirmed the formation of a heterojunction composite since their images showed multi-stacked layers of MoS₂ nanosheets uniformly grown onto the octahedral shape of Cu/Co-MOF. Furthermore, the optical and piezo-electrochemical properties of the MoS₂@Cu/Co-MOF heterostructure were improved as confirmed by UV-DRS and CA. The internal piezoelectric field generated through ultrasonic vibration improved the separation of photogenerated charge carriers, thus enhancing photocatalytic performance. Under synergistic effect (combination of photocatalysis and piezocatalysis), MoS₂@Cu/Co-MOF heterojunction composite exhibited maximum hydrogen (H₂) production of 1308.028 µmol, which was greater than under individual processes including photocatalysis (832.381 µmol) and piezocatalysis (1010.749 µmol). Furthermore, the MoS₂@Cu/Co-MOF heterojunction composite achieved the highest degradation efficiency of 82 % under both light and ultrasonic irradiation. The plausible hydrogen production and degradation mechanism was proposed. This study offers valuable insights into the development of highly efficient and versatile heterostructure materials aimed at producing clean hydrogen energy and water.