Advanced LDH-derived Ag@NiO/Ag2CrO4 heterojunction photocatalyst for rapid dye degradation

Abstract

This work unveils a superior plasmonic photocatalyst synthesized through the strategic integration of metallic Ag during NiCr LDH synthesis. The catalyst synthesis involved the formation of modified NiCr LDH, by the incorporation of a metallic Ag solution and subsequent air heat treatment, leading to the in-situ development of the mixed metal oxide Ag@NiO/Ag₂CrO₄ (ANC). The ANC photocatalyst exhibits strong visible-light absorption and suitably positioned band edges, forming a Z-scheme heterojunction that facilitates efficient charge transfer and enhances redox reactivity. The efficacy of the photocatalyst was evaluated by the degradation of MB and RhB dye, revealing that the heterojunction photocatalyst outperformed the LDH derived NiO (NC) counterpart by 34 fold and 1.4 fold in MB and RhB degradation, respectively. The improved catalytic performance mainly stems from its efficient harvesting of visible light, and the plasmonic effects, including local surface plasmon resonance (LSPR) and plasmon induced resonant energy transfer (PIRET). The PIRET phenomena enabled by Ag nanoparticles plays a crucial intermediary role in sustaining an efficient Z-scheme charge transfer between Ag₂CrO₄ and NiO. The key significance of this study lies in its innovative synthesis strategy, wherein NiCr LDH serves as a transformative precursor, strategically engineered to develop highly active photocatalysts through the incorporation of plasmonic Ag.