Innovative complex perovskites for efficient hydrogen Evolution: A DFT-Based design strategy

Abstract

Recently, hydrogen, a high-energy, non-polluting fuel, has attracted considerable attention. Perovskites are of great interest in the hydrogen energy field due to their attractive properties. Herein, first-time novel complex perovskites [K(Mg+2Nb+5)O3] were designed computationally. The DFT has been utilized to systematically examine structural, electronic, optical, elastic, and mechanical properties to explore their potential applications in producing solar-driven hydrogen. Complex compositions (varying Mg+2 and Nb+5 concentrations) likely to adopt cubic or pseudocubic (a≈b≈c) perovskite structures based on structural parameters and the Goldschmidt tolerance factor. Including Nb in the crystal structure plays a significant role in shaping the band gap energy. Formation enthalpies show that all compounds are dynamically stable and synthesizable. Absorption coefficients (∼105cm-1) and effective optical responsiveness in UV and visible range make them a potential candidate for light energy harvesting. The computed high dielectric constant, a declining trend in refractive index and reflectivity, and minimum energy loss characteristics are attractive and are suitable for optoelectronic applications. Mechanical elements, ductility, anisotropy, toughness, and crack resistance proposed that compounds are highly desirable for various applications. The proposed complex compositions could catalyze efficient hydrogen evolution reactions (HERs) due to their suitable bandgap energies, suitable absorption coefficients, and alignment of the band edges regarding the redox potential of water.