الفهرس 
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Abstract
A key challenge in photoelectrochemical water splitting is fabricating nanostructured photoelectrodes with desirable properties. Herein, Ni-doped BaTiO3 hollow spheres (HS) supported on reduced graphene oxide (RGO) nanocomposite were successfully synthesized by aerosol spray drying method. Former spheres consisted of small nanoparticles with sizes 5–20 nm possessing high porosity and large area. characterizations were done by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), high-resolution transmission electron microscopy (HRTEM), and field emission scanning electron microscopy (FESEM). Ni-doped BaTiO3 HS/RGO nanocomposites as photoanodes exhibited an enhanced photoelectrochemical performance and long-term stability compared to BaTiO3 HS and BaTiO3 HS/RGO. The photocurrent density of Ni-doped BaTiO3 HS/RGO photoanode revealed 8.14 μA cm-2 which is 37% more than BaTiO3 HS. from electrochemical impedance spectroscopy (EIS) analysis, Ni-doped BaTiO3 HS/RGO exhibited the lowest charge transfer resistance in comparison with BaTiO3 HS and BaTiO3 HS/RGO which leads to enhancement in the electrocatalytic activity. The successful doping of BaTiO3 HS by Ni and its loading over RGO increases the separation rate of photogenerated electrons and holes and improved the light-harvesting. Ni-doped BaTiO3 HS/RGO as photo-electrocatalyst exhibits excellent activity toward water oxidation capability and presents a new approach for high-efficient future photo-electrocatalysis.
Extending to this work reported on electrochemical Water splitting as a key technology for replacing fossil fuels with environmentally friendly alternatives. Perovskite oxides are very promising and effective electro-catalysts for a variety of energy-related applications, due to their low cost, versatile structure, and high catalytic activity. Herein, Ni-doped BaTiO3 hollow spheres supported by reduced graphene oxide succeed as bifunctional electro-catalysts that act simultaneously for the oxygen reduction reaction (ORR) and the oxygen evolution reaction (OER). Ni-doped BaTiO3/RGO nanocomposite exhibits high electrochemical activity and stability for both the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER). Ni-doped BaTiO3/RGO demonstrates an outstanding current density up to 100 mA cm−2 at a potential of 1.6V vs. RHE, which is 5 times higher than BaTiO3.
Keywords: Hollow spheres; nanocomposites; BaTiO3; doping; graphene; photoelectrochemical water splitting; Perovskite oxides; bifunctional catalyst; oxygen reduction reaction; oxygen evolution reaction.