Surface decoration of MnWO4 nanoparticles with g-C3N4 nanosheets to build hetero-structure and its structural, optical and enhanced visible light photocatalytic activity

In this study, we report the synthesis of manganese tungstate (MnWO4)/graphitic carbon nitrides (g-C3N4) hybrid photo
catalysts by simple hydrothermal method. The prepared photocatalysts have been characterized by X-ray diffraction (XRD),
transmission electron microscopy (TEM), energy dispersive X-ray (EDX) analysis, X-ray photoelectron spectroscopy (XPS),
Raman spectroscopy, photoluminescence spectroscopy (PL) and UV–visible spectroscopy. XRD and TEM results reveal that
the both pure and composite samples have monoclinic wolframite structure with spherical nanoparticles, which is decorated
on the surface of g-C3N4 sheets. A considerable red shift in the absorption and narrowing the band gap (3.02–2.55 eV)
energy was observed in the MnWO4/g-C3N4 composite samples. The photocatalytic measurements exhibit that the optimized
photocatalyst (15 wt%-MnWO4/g-C3N4) show high degradation efficiency (98%) and long-term stability towards rhodamine
(RhB) dye under visible light irradiation. The J-V characteristics reveal that MnWO4/g-C3N4 photoanode show high photo
conversion efficiency (PCE%) of 7.15%, which is higher than that of pure MnWO4 (2.34%). The significant enhancement in
the photocatalytic behavior is due to the coactions between the g-C3N4 nanosheets and MnWO4 nanoparticles.