AB-INITIO CALCULATIONS OF THE RHODIUM-DOPED (001) SURFACE OF THE RHOMBOHEDRAL PHASE BaTiO₃

Abstract

The advancement of effective, durable, and economically viable photocatalytic systems aimed at solar-driven water splitting into hydrogen and oxygen represents a strategically vital pathway for future fuel and chemical production from renewable sources. Water splitting is a promising strategy for the sustainable production of renewable hydrogen and for addressing the global energy and environmental crisis. However, the large-scale application of this method is limited by the low efficiency and high cost of solar water splitting systems. The search for economical, efficient, and stable photocatalysts is crucial in the development of solar water splitting technologies. Perovskite-based photocatalysts have recently attracted considerable attention for use in solar water splitting processes due to their simple structure and flexible composition. BaTiO3 is a promising photocatalyst because of its adjustable electronic structure. Initially considered a poor photocatalyst due to its wide band gap, this material has become the focus of various strategies aimed at reducing the band gap. In this paper, we study the effect of Rh doping on the electronic structure of the (001) BaTiO3 perovskite surface. Theoretical results show that Rh atoms can occupy both sites simultaneously, or only Ti sites, or Ba sites. The electronic structure was modeled for two conditions. When Rh atoms occupy one Ba position and one Ti position, the electronic structure shows the presence of an acceptor level within the band gap above the Fermi level, effectively reducing the band gap of the material.