Synthesis and fabrication of hetero-structured metal oxide nanoarrays and their characterization for water splitting application

In this work we report hybrid synthesis of hetero-structured metal oxide nanoarrays namely ZnO/Ga2O3 and WO3/BiVO 4 on desirable substrates for photoelectrochemical (PEC) water splitting under visible light. These hetero-nanostructured arrays were synthesized and fabricated by hybrid two-steps, physical approach and hydrothermal methods.;Hetero-structured ZnO/Ga2O3 was synthesized and fabricated on indium oxide tin oxide (ITO) substrate from alkaline (pH = ~13) aqueous solution containing ZnO and Ga2O3 individually. XRD analysis revealed that the fabrication of ZnO/Ga2O3 hetero-structured. FESEM characterization showed the formation of well-aligned nanorods arrays along with hexagonal shape on the entire surface of the ITO substrate. Optical properties confirmed the ability of ZnO/Ga2O 3 thin film for harvesting visible light efficiently. Furthermore the photoelectrochemical properties was investigated under visible light with chronoamperometry (CA) and linear sweep voltammetry potentiostatic (LSVP) techniques. The photoresponse increased with increasing Ga2O 3 amount and reached the peak value 0.60 mA/cm2 with coating of thin layer of gold due to surface plasmon resonance of gold nanoparticles.;In addition WO3/BiVO4 hybrid metal oxide nanoflakes was synthesized and fabricated on (ITO) substrate from strong acidic (pH = ∼1) aqueous solution containing WO3 and BiVO4 separately. XRD pattern showed the formation of WO3/BiVO4 hetero-structured metal oxide. FESEM analysis revealed the growth of nanoflakes. UV -- VIS analysis explored the possibility of visible light harvesting of WO 3/BiVO4 thin film. CA and LSVP were investigated for WO 3/BiVO4 photoanode and illustrated the stability of thin film versus photo-corrosion and response enhanced with increasing annealing temperature. The peak value was 0.109 mA/cm2 for WO3/BiVO 4 thin film.