A computational investigation of novel double perovskite oxides Ba ₂ XReO ₆ (X = Li, Na) for optoelectronic and photocatalytic applications

Double perovskite oxides have garnered significant attention as a sustainable alternative to lead-based perovskites. In this study, we conducted a comprehensive investigation into the structural, elastic, optoelectronic and photocatalytic properties of Ba 2 XReO 6 (X [Formula: see text] Li, Na) double perovskite oxides using first-principles computations. The stability of the Ba 2 XReO 6 compound has been assessed by formation enthalpy, tolerance factor, phonon dispersion curves and AIMD simulations. Furthermore, the elastic stability has been confirmed by Born stability criteria. Interestingly, our computations reveal that our studied compounds are stable in all aspects. The electronic band structure analysis indicated that Ba 2 XReO 6 compounds are semiconductors with a direct band gap of 1.891 and 1.939[Formula: see text]eV for Ba 2 LiReO 6 and Ba 2 NaReO 6 perovskites, respectively. Several optical spectra have been computed and analyzed. These findings are consistent with the functional criteria required for solar photocatalytic hydrogen production and indicate that these materials exhibit properties similar to known hydrogen-evolving photocatalysts. Therefore, Ba 2 LiReO 6 and Ba 2 NaReO 6 can be regarded as promising candidates for efficient solar-driven overall water splitting. The findings of this study strongly suggest that Ba 2 XReO 6 compounds are promising candidates for an eco-friendly energy solution for optoelectronic and photocatalytic applications.