Porous Nanosheets and Excellent Charge Carrier Dynamics in Ag⁺‐Doped Na_0.5Bi_2.5Nb₂O₉ Aurivillius‐Phase Layered Perovskite for Enhanced Visible‐Light Photocatalytic Activity

The new Aurivillius layered perovskite compounds, Ag_xNa_0.5-xBi_2.5Nb₂O₉ (AGBNO), were successfully synthesized using a hydrothermal technique followed by conventional, microwave-assisted, and acid-assisted ion exchange procedures. The formation of these compounds was evidenced by several techniques. A single-phase crystal structure was identified by XRD patterns, and expanded lattice parameters were revealed by crystal structure refinement. Chemical composition was verified by EDS, XPS, and ICP-OES analyses. Bandgap energies remained similar to the parent Na_0.5Bi_2.5Nb₂O₉ host material. Ag⁺ incorporation significantly enhanced photocatalytic performance for Rhodamine B degradation under visible light, which was attributed to the intrinsic catalytic properties of Ag⁺ as a noble metal cation. The variations in photocatalytic activities among the series of Ag⁺-doped samples produced were associated with differences in morphology, specific surface area, and charge carrier dynamics. The AGBNO sample prepared via acid-assisted ion exchange exhibited the highest photocatalytic efficiency, which was attributed to its highly porous nanosheet morphology, largest surface area, and excellent charge carrier dynamics, including high initial charge carrier concentration, optimal lifetime, high charge mobility, efficient charge separation, and transfer. Overall, this study demonstrates the potential of designing Aurivillius-phase layered perovskite photocatalysts with enhanced activity for wastewater remediation and environmental applications through noble metal cation doping.