Research Projects

The advancement of functional materials for sustainable energy applications is a primary focus in materials science research, with double perovskite-type materials emerging as a promising class due to their structural flexibility, intrinsic chemical robustness, and wide-ranging potential for tailored properties. Double perovskites, typically represented by the generic formula A2BBX6 are characterized by unique lattice structures comprising two distinct metal cations at B- and B’-sites (here, Alkaline earth metals and d-block elements), an A-site cation (Alkali metals), and a variable X-site anion (Halogens, and Hydrogen). This compositional variability allows for significant tuning of the material’s properties to meet multi-functional requirements, specifically for photocatalytic water splitting and solid-state hydrogen storage materials. Both applications are of immense interest due to their capability of zero-emission of pollutants. In photocatalytic water splitting, the tuneable electronic band gap, and high stability of double perovskites allow for efficient light absorption and charge separation, facilitating hydrogen production with minimal environmental impact. Also, the ability to incorporate hydrogen into the lattice structure (A2BB’H6) provides a safe, compact, and emission-free solution for hydrogen storage media, a critical component for developing a clean fuel system. For a material, to efficiently derive photocatalytic water splitting, its band gap must ideally lie in the range of 1.8-3.0 eV, while for hydrogen storage the benchmark gravimetric hydrogen storage density (Cwt %) should be greater than 5.5 % (according to US-Department of Energy). The preliminary investigations of these compounds have demonstrated their suitability for the aforementioned applications by satisfying the above criteria for water splitting and hydrogen storage. The investigation of the proposed materials will be broadened to include the analysis of their vacancy-ordered structures (A2BX6) for the same applications outlined above. The stability of the A2BX6 perovskite-type structures relies on the B-site cation and often offers a direct electronic band gap. Moreover, the study will be extended to examine the surface slab cleavage from the bulk crystal structures and incorporate a solvent model to provide a more realistic representation of the photocatalytic water splitting mechanism. Additionally, the influence of surface layer thickness and cleavage direction referred to as ‘anisotropic cleavage’, will be explored to enhance hydrogen storage capacity. Herein, all the proposed work will be performed under the frameworks of density functional theory (DFT).

double perovskites, DFT, PCT water splitting, hydrogen evolution reaction, oxygen evolution reaction, hydrogen storage