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

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 Dy^3+: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.