Designing a NiFe-LDH/MnO2 heterojunction to improve the photocatalytic activity for NOx removal under visible light
María Ángeles Oliva, David Giraldo, Paloma Almodóvar, F. Martı́n, Marı́a Luisa López, I. Pavlović, Luis Sánchez
Abstract
2D/2D heterojunctions between ultrathin NiFe-CO3 layered double hydroxide (LDH) and varying amounts of birnessite (δ-MnO2) were prepared using an environmentally friendly and cost-effective self-assembly method. The prepared samples have proven to be efficient in their application, mitigating NOx emissions via a photooxidative process. The effective creation of 2D/2D NiFe–LDH/MnO2 heterojunctions has been verified through a variety of characterisation techniques, such as XRD, FT-IR, TGA, XFR, N2 adsorption–desorption isotherms, HRTEM and SEM images, EDX, and XPS. Photocatalytic measurements have indicated that the heterojunction formed between NiFe-LDH and MnO2 modifies its photoconductive behaviour, significantly enhancing the visible light photocatalytic performance of the partners. Finally, the optimal relationship between NiFe-LDH and MnO2 in the photocatalytic process was studied. It was found that a ratio of 10:1, respectively, exhibited superior properties compared to the other composites, highlighting the best performance in the degradation of NO under visible light and notable stability during the recycling process.