Impacts of metal oxides on the structural, optical, dielectric and photocatalytic properties of synthesized ternary composite (Nb2O5/MoS2/Graphene)

The principal objective is the preparation of visible light active photocatalysts to explore hydrogen evolution from water splitting. Synthesization of the composite materials was followed by two step simple hydrothermal method. Initially, a ternary composite consisting of Nb2O5, MoS2 and graphene was prepared by hydrothermal method. For further improvement in the hydrogen evolution rate and photocatalytic efficiency, the ternary composite Nb2O5/MoS2/Graphene (NMG) was combined hydrothermally with different metal oxides (TiO2, ZnO, Cu2O, CdO, NiO and MgO). Purposive characterization of the synthesized materials were accomplished by XRD, SEM, TEM, FTIR, PL and UV-DRS techniques to analyze their physical and chemical properties. The crystallite sizes were estimated from XRD and found to vary in the range 10.69-47.8 nm. Particle sizes from SEM were found in the range 41-98 nm. FTIR spectra confirms the bands representing Nb-O-Nb and Nb=O stretching. The band gaps of composites (NMG/metal oxides) were examined in the range of 2.40-3.08ev. Room temperature dielectric behaviors of the synthesized nanocomposites were observed and found a decreasing behavior in dielectric constant and dielectric loss with increasing frequency. Conclusive outcomes of synthesized samples exhibited improved photocatalytic activity in terms of degradation of methyl orange and hydrogen evolution from water splitting.