Construction of 2D MoS2@ZnO heterojunction as superior photocatalyst for highly efficient and selective CO2 conversion into liquid fuel

An advanced photocatalyst heterojunction comprised of 2D sheets of MoS2 and diamond-like shape ZnO nanoparticles was successfully synthesized via a simple calcination route. The structural properties were investigated by X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscope (TEM), UV-visible-NIR absorption spectrophotometer, Photoluminescence (PL), X-ray photoelectron spectroscopy (XPS), and Raman analysis. The morphology investigations show the wrapping of MoS2 nanosheets around the agglomerated ZnO nanoparticles forming a hollow-like shaped structure. Moreover, ZnO/MoS2 luminescence revealed a remarkable charge carriers' separation. The photocatalytic reduction of CO2 was performed under UV light irradiation of a 150 W Hg lamp in three different solvents. ZnO/MoS2 exhibited high photocatalytic activity towards CO2 photoreduction into CH3OH and minor traces of CH3CHO, and C2H5OH. Methanol was the dominant product with a maximum yield of 170.5 mu mol/g. The high photocatalytic activity of ZnO/MoS2 may be attributed to accumulation of electrons on the surface of 2D-MoS2 which granted electrons a great mobility that supported the charge carrier's separation. In addition, the hollow-like shaped structure may contribute to greater light absorption through photon refractions inside the shell which increases the photocatalytic performance.