title: Luminol-silver nitrate chemiluminescence enhancement induced by cobalt ferrite nanoparticles.
abstract: CoFe(2)O(4) nanoparticles (NPs) could stimulate the weak chemiluminescence (CL) system of luminol and AgNO(3), resulting in a strong CL emission. The UV-visible spectra, X-ray photoelectron spectra and TEM images of the investigated system revealed that AgNO(3) was reduced by luminol to Ag in the presence of CoFe(2)O(4) NPs and the formed Ag covered the surface of CoFe(2)O(4) NPs, resulting in CoFe(2)O(4)-Ag core-shell nanoparticles. Investigation of the CL reaction kinetics demonstrated that the reaction among luminol, AgNO(3) and CoFe(2)O(4) NPs was fast at the beginning and slowed down later. The CL spectra of the luminol - AgNO(3) - CoFe(2)O(4) NPs system indicated that the luminophor was still an electronically excited 3-aminophthalate anion. A CL mechanism has been postulated. When the CoFe(2)O(4) NPs were injected into the mixture of luminol and AgNO(3), they catalyzed the reduction of AgNO(3) by luminol to produce luminol radicals and Ag, which immediately covered the CoFe(2)O(4) NPs to form CoFe(2)O(4)-Ag core-shell nanoparticles, and the luminol radicals reacted with the dissolved oxygen, leading to a strong CL emission. With the continuous deposition of Ag on the surface of CoFe(2)O(4) NPs, the catalytic activity of the core-shell nanoparticles was inhibited and a decrease in CL intensity was observed and also a slow growth of shell on the nanoparticles.
authors.affiliation: The Key Laboratory of Luminescence and Realtime Analysis, Ministry of Education, College of Chemistry and Chemical Engineering, Southwest University, Chongqing, 400715, China.
authors.forename: Wenbing
authors.initials: W
authors.lastname: Shi
authors.forename: Hui
authors.initials: H
authors.lastname: Wang
authors.forename: Yuming
authors.initials: Y
authors.lastname: Huang
mesh_terms: D003035:Cobalt / Q000737:chemistry*; D049449:Luminescence; D008165:Luminol / Q000737:chemistry*; D053768:Metal Nanoparticles; D046529:Microscopy, Electron, Transmission; D012835:Silver Nitrate / Q000737:chemistry*; D013056:Spectrophotometry, Ultraviolet
chemical_list: D003035:Cobalt; D008165:Luminol; D012835:Silver Nitrate