A study of the effect of microwave treatment on metal zeolites and their use as photocatalysts toward naptalam

A new route to fabricate silver and gold-based material incorporated into the Y zeolite framework is reported. X-ray fluorescence (XRF), X-ray photoelectron spectroscopy (XPS), UV–vis diffuse reflectance, and low-temperature steady-state photoluminescence spectroscopic results indicate the formation of metallic silver and gold as well as ionic clusters on the zeolite framework. Microwave treatment affects the surface morphology and the metal content of different catalyst systems. The photodecomposition of the pesticide naptalam is enhanced in the presence of silver and gold exchanged into zeolite Y catalysts. The largest catalytic activity was observed for the AgAuYm catalyst where an increase in the decomposition rate by 20-fold was observed compared to the uncatalyzed irradiated naptalam solution. While the microwave treated mixed sample (Ag-AuYm) acts as a good catalyst for the degradation of naptalam, the untreated sample (Ag-AuY) provides a selective surface that completely adsorbs naptalam from solution. GC–MS, HPLC, and synchronous scan luminescence spectra (SSLS) results show the formation of three products namely, α-naphthylamine, phthalic acid, and N-1-naphthylphthalimide for the photodecomposition of naptalam irradiated at 254 nm in aqueous solution. This is in contrast to the catalyzed reactions where N-1-naphthylphthalimide is the major product.

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► We have developed a novel highly active catalyst for the photodegradation of the pesticide naptalam.
► This catalyst is prepared by doping Ag and Au nanoparticles into Y zeolite and then digested by microwave treatment.
► The microwave process, which enhances the formation of mixed Ag and Au nanoclusters, is crucial for the catalytic activity.
► The largest catalytic activity was observed for the AgAuYm catalyst where a 20-fold increase in the decomposition rate was observed.
► The untreated sample (Ag-AuY) provides a selective surface that completely adsorbs naptalam from solution.