Synthesis of $NaTaO_3$ by spray pyrolysis and evaluation of photocatalytic activity for hydrogen production by water splitting

Abstract

The photocatalytic production of hydrogen from water using solar energy is potentially a clean and renewable source for hydrogen fuel. In this thesis, $NaTaO_3$ was prepared by spray pyrolysis without post-treatment for water splitting in pure water under UV light irradiation. Precursor solution was prepared from $NaTaO_3$ and $Ta(OC_2H_5)_5$ as precursors in nitric acid solution and spray pyrolyzed at various temperatures. XRD, SEM, $N_2$ adsorption/desorption method and UV-vis spectroscopy were used to characterize the prepared photocatalysts. NiO was loaded on $NaTaO_3$ synthesized by conventional solid-state reaction and spray pyrolysis to enhance charge separation, resulting in the enhancement photocatalytic activity for water splitting into $H_2$ and $O_2$ in a stoichiometric ratio. When NiO was loaded on $NaTaO_3$ prepared by spray pyrolysis, high photocatalytic activity for water splitting was obtained. It was because of highly dispersion of NiO particles on surface of $NaTaO_3$ observed from TEM caused by high surface area of the $NaTaO_3$ prepared. The quantum yield of $NiO(0.05wt%)/NaTaO_3$ prepared by spray pyrolysis was 3.1% by chemical actinometry using potassium ferrioxalate. Also, the activity of photocatalyst evaluated by practical term was 59.2μmol/gㆍLㆍhㆍW.