Organic Dye Photodegradation Using Niobium-Alkali Perovskite Photocatalysts: The Effect of the Alkali

This study combines experimental and density functional theory (DFT) to evaluate the influence of alkaline cation characteristics on the electronic structure and photodegradation efficacy of organic dyes in MNbO3 (M = Na, K) perovskites. The X-ray Photoelectron Spectroscopy (XPS) and X-ray Absorption Near Edge Spectroscopy (XANES) spectra at the Nb edge of the Perovskites were employed to characterize its chemical and structural properties. The DFT calculations were carried out to simulate XANES spectra as well as the structural and electrical properties of KNbO3 and NaNbO3. Our results show that the simulated and experimental XANES spectra are similar, indicating that the computational simulations were able to capture the local structure of the niobate samples. In addition, a photocatalytic experiment was conducted to benchmark the methylene blue consumption efficiency between different niobates. The findings demonstrated that KNbO3 is more efficient than NaNbO3 for methylene blue UV photocatalytic degradation, which is associated with their electronic properties. This arises as a direct result of the variably deformed NbO6 octahedra resulting from the different alkali used. Our findings facilitate the advancement of stable and abundantly available photocatalysts, which may be employed for energy-intensive processes such as the mineralization of organic water pollutants and hydrogen production by water splitting.