One-step mechanochemical synthesis of plasmonic Ag/Zn-Al LDH with excellent photocatalytic activity

摘要

A series of Ag/Zn-Al layered double hydroxide composites were successfully synthesized by a mechanochemical method, and their photocatalytic activity as methyl orange (MO) degradation was investigated. The nanoscale composites showed excellent photocatalytic activity and enabled simply over 95% degradation of MO under visible light irradiation in 180 min. Based on the results from EIS and PL analyses, the enhancement of photocatalytic efficiency was mainly attributed to the surface plasmon resonance effect of Ag nanoparticles and the Schottky barrier between Ag and LDH, with efficient adsorption of resonant photons on the composites and subsequent electron transfer to the conduction band of LDH to promote the separation efficiency of photogenerated electrons and holes. 4%Ag/LDH exhibited the highest photocatalytic activity with high stability after multiple running cycles. The electron spin resonance revealed that center dot OH was the dominant active species in the photocatalysis process. Considering the limited choice of soluble noble metal salts to serve as starting samples for loading preparation, this work allowed the direct use of Ag metal instead of very expensive soluble salts for sample preparation, providing a facile novel green and nonthermal method to assemble metal-semiconductor combination by co-grinding metal element with semiconductor raw materials.