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We synthesized NiO-loaded TiO_2 porous p-n junctions by electrophoretic enhanced micro arc oxidation(EEMAO) technique which is a relatively simple and new method for producing composite coatings.Phase structure,chemical composition,and surface morphology of the NiO—TiO_2 coatings were investigated by X-ray diffraction(XRD),X-ray photoelectron spectroscopy(XPS),and scanning electron microscopy(SEM) techniques,respectively.Photocatalytic efficiency of the samples was studied through measuring the decomposition rate of 4-chlorophenol under UV irradiation.Results showed that the coatings mainly consisted of anatase,rutile,and nickel oxide phases.It was observed that a finer surface morphology,i.e.smaller pores,was obtained at lower voltages.Besides,the amount of nickel oxide loaded to the TiO_2 host increased with the voltage.The NiO-TiO_2 composite coatings showed a higher photoactivity than pure TiO_2 coatings revealing the effective role of NiO in decreasing the recombination rate of photogenerated electrons and holes.The maximum photocatalytic reaction rate constants for TiO_2and NiO—TiO_2 samples were obtained as 0.0064 and 0.0131 min~(-1),respectively.We also found that there was an optimum concentration of NiO where a maximum photocatalytic activity was achieved.A correlation between growth variables,structure,and photocatalytic efficiency was established.
We synthesized NiO-loaded TiO_2 porous pn junctions by electrophoretic enhanced micro arc oxidation (EEMAO) technique which is a relatively simple and new method for producing composite coatings. Phase structure, chemical composition, and surface morphology of the NiO-TiO_2 coatings were investigated by X-ray photoelectron spectroscopy (XPS), and scanning electron microscopy (SEM) techniques, respectively. Photocatalytic efficiency of the samples was studied through measuring the decomposition rate of 4-chlorophenol under UV irradiation. Results showed that the coatings mainly consisted of anatase, rutile, and nickel oxide phases. It was observed that a finer surface morphology, iesmaller pores, was obtained at lower voltages. Besides, the amount of nickel oxide loaded to the TiO 2 host increased with the voltage The NiO-TiO 2 composite coatings showed a higher photoactivity than pure TiO 2 coatings revealing the effective role of NiO in decreasing the recombination rate of photogenerated electrons and holes.The maximum photocatalytic reaction rate constants for TiO_2and NiO-TiO_2 samples were obtained as 0.0064 and 0.0131 min -1, respectively.We also found that there was an optimum concentration of NiO where a maximum photocatalytic activity was achieved .A correlation between growth variables, structure, and photocatalytic efficiency was established.