A novel Dy³⁺ modified Zn<inf>2</inf>Ti<inf>3</inf>O<inf>8</inf> nanoparticles for efficient hydrogen production photocatalysis

Abstract

Novel Dy3+:Zn2Ti3O8 (Dy3+:ZTO) nano-photocatalysts with different Dy3+ concentrations were applied to enhance the photocatalytic hydrogen generation activity from sodium borohydride hydrolysis reaction. XRD and Raman measurements confirm the formation of cubic Zn2Ti3O8 phase as a major phase in addition to minor TiO2 phase. The analysis of XPS spectra shows the existence of lattice oxygen (LO) and non-lattice oxygen (NLO) where 0.07 mol Dy3+:ZTO has the highest percentage of NLO compared to the undoped photocatalyst. The energy gap value decreases with increasing doping concentrations (3.137 eV for 0.07 mol Dy3+:ZTO). The degree of disorder, represented by Urbach energy, has an optimum high value (0.169 eV) for 0.07 mol Dy3+:ZTO. The photoluminescence studies revealed that Dy3+ dopant can effectively separate the photogenerated electron/hole pairs in the ZTO. These photocatalysts have strong photocatalytic hydrogen generation. The most active nano-photocatalyst towards hydrogen generation was 0.07 mol Dy3+: ZTO (5.6 mmol/g). The highest photocatalytic activity for 0.07 mol Dy3+: ZTO are attributed to the lower recombination rate associated with the higher disorder and oxygen vacancies relative to the undoped photocatalyst. The stability and reusability of the most active photocatalyst were investigated. The results confirm that the developed photocatalyst has good durability in hydrogen generation reaction. The results, moreover, revealed that Dy3+: ZTO nano-photocatalyst is a promising nanomaterial in the field of energy production.