A novel Dy3+ modified Zn2Ti3O8 nanoparticles for efficient hydrogen production photocatalysis

Abstract

Novel Dy 3+ :Zn 2 Ti 3 O 8 (Dy 3+ :ZTO) nano-photocatalysts with different Dy 3+ concentrations were applied to enhance the photocatalytic hydrogen generation activity from sodium borohydride hydrolysis reaction. XRD and Raman measurements confirm the formation of cubic Zn 2 Ti 3 O 8 phase as a major phase in addition to minor TiO 2 phase. The analysis of XPS spectra shows the existence of lattice oxygen (LO) and non-lattice oxygen (NLO) where 0.07 mol Dy 3+ :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 Dy 3+ :ZTO). The degree of disorder, represented by Urbach energy, has an optimum high value (0.169 eV) for 0.07 mol Dy 3+: ZTO. The photoluminescence studies revealed that Dy 3+ 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 Dy 3+ : ZTO (5.6 mmol/g). The highest photocatalytic activity for 0.07 mol Dy 3+ : 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 Dy 3+ : ZTO nano-photocatalyst is a promising nanomaterial in the field of energy production. Graphical illustration for the hydrogen generation. • Novel Dy 3+ :Zn 2 Ti 3 O 8 (Dy 3+ :ZTO) nano-photocatalysts were prepared. • Dy 3+ dopant can effectively separate the photogenerated carriers in the ZTO. • Dy 3+ :ZTO enhances the photocatalytic activity of hydrogen generation. • Catalyst reusability and stability of 0.07 mol Dy 3+ :ZTO was tested.