Is Rb2PtX6 (X = Cl, Br, and I) a promising Pb-free vacancy-ordered double perovskites for photoelectrochemical water splitting applications?

In this work, the band structure feature, charge carrier mobility, optical properties, and photocatalytic performance of platinum-based vacancy-ordered double perovskites Rb2PtX6 (X = Cl, Br, and I) are investigated. The results show the semiconducting character of all three materials with band gap values equal to 3.39 eV, 2.76 eV, and 1.45 eV, for Rb2PtCl6, Rb2PtBr6, and Rb2PtI6, respectively. Furthermore, the calculated electron and hole effective masses yield a higher relative mass of hole-electron pairs (D), resulting in a slow recombination rate in these materials. The optical properties are also calculated, where the entitled materials show high absorption intensities in the visible and ultraviolet regions. Moreover, it is discovered that the Rb2PtCl6 and Rb2PtBr6 compounds can produce both oxygen and hydrogen at the same time. In contrast, the Rb2PtI6 material has a poor water-splitting ability and may be a promising photocatalyst for CO2 photoreduction.

Automated summary

In this study, the band structure, charge carrier mobility, optical properties, and photocatalytic performance of platinum-based vacancy-ordered double perovskites Rb2PtX6 (X = Cl, Br, and I) were investigated. The materials exhibited semiconducting behavior, with different band gap values. Additionally, the materials showed high absorption intensities in the visible and ultraviolet regions, making them potential candidates for photocatalytic applications.