New Chemiluminescence Research Methods For Characterization Of Nanomaterials Structure

The electron,geometry and surface structures characteristics of nanomaterials affect the photoelectric and catalytic properties.Efficient determination of structures contributes to a better understanding for their effect on nanomaterials.However,it is difficult to measure the surface and electronic structure due to their complex composition and unstability.Currently,the characterization instruments commonly used for determination of the nanomaterials structure include X-ray photoelectron spectrometer,electron paramagnetic spectrometer and transmission electron microscope,etc.Nevertheless,these techniques require not only harsh measuring environment and complex operations,but time-consuming detection.Thus,it is necessary to develop a simple and rapid characterization method for the structure determination of nanomaterials.Chemiluminescence(CL)assay has the merits of simple environment,convenient instrumental operation and rapid signal response,which can make up the drawback of the above technique.In this work,based on the characteristic that CL signal depends on the structure of nanomaterials,the characterization method of CL was established for rapidly characterize the surface oxygen states(O-states)on carbon quantum dots and crystal facet in noble metal nanocrystal(NCs)by CL probes of peroxynitrite and propanol.Moreover,a method was established for controlling CL selectivity of hypochlorous acid by highest occupied molecular orbital(HOMO)energy level-mediated CL,which may offer valuable guidance to solve the blindness problem of reactive oxygen species screening.The specific research contents of this paper are as follows:(1)Since the CL of carbon quantum dots was derived from the smaller energy separation,a rapid CL method for screening the surface O-states of carbon quantum dots was established in view of this property.These carbon quantum dots with different contents of O-states were synthesized by controlling the doping contents of sulfur and were used to explore luminescence response of peroxynitrite-carbon quantum dots CL system.It was found that CL intensity was proportional to the content of C-O group-related O-states.Meanwhile,the abundant C-O functional groups in the carbon quantum dots with high O-states can promote the generation of small gaps and facilitate the free radical intermediates to inject electrons/holes into the energy gap of the carbon quantum dots,thus improve the CL intensity of carbon quantum dots.The C-O group-related O-states in sulfur-doped carbon quantum dots measured by the peroxynitrite CL probe were consistent with X-ray photoelectron spectroscopy characterization.Its practicability was verified by CL detection of different O-states in phosphorus-doped carbon quantum dots.It indicated that the O-states in different types of nanoparticles can be screening by CL probe.(2)Based on the crystal facet-dependent cataluminescence characteristics of noble metal NCs,the differentiation of noble metal crystal facets was realized.The Pd@Au NCs with different crystal facets were loaded on layered double hydroxide,and the influence of crystal facets on propanol-triggered cataluminescence was investigated.Excited oxygen molecules on layered double hydroxide-supported Pd@Au NCs participated in catalytic oxidation reaction,which transformed propanol into excited carbon dioxide accompanied by light emission.Abundant negative charges on the high-index facets of Pd@Au NCs facilitated electron transfer between crystals facets and propanol,resulting in stronger cataluminescence.The crystal facets of noble metal NCs were screening via the positive correlation between propanol-triggered cataluminescence intensity and the crystal facets index of Pd@Au NCs.Its universality had further been verified by screening crystal facets in layered double hydroxide-supported Pd NCs by the proposed strategy.Meanwhile,the recognition of mixed crystal facets in the Pd@Au NCs could be realized with a sensor array based on linear discriminant analysis and hierarchical cluster analysis.(3)According to the redox potential relationship between HOMO energy level of nanomaterials and reactive oxygen species,a method was established for controlling CL selectivity of hypochlorous acid by energy level structure-mediated CL.Among the reactive oxygen species with the ability to inject hole into the HOMO energy level of glutathione stabilized-gold nanoclusters,hypochlorous acid and peroxynitrite can lead to the breaking of Au(Ⅰ)-complex ligand with polypeptide-like skeleton,resulting in the collapse of the energy level structure of gold nanoclusters with the weak CL signal.On the other hand,the modified oxidation of hypochlorous acid on the side chain of the polypeptide skeleton-like guaranteed the integrity of the energy level structure,which was conducive to the recombination of electrons and holes in the CL reaction with strong CL intensity.Thus,hypochlorous acid showed excellent CL selectivity.According to the mechanism of energy level structure-dominated CL,the CL selectivity of reactive oxygen species was determined by using graphene carbon nitride with similar HOMO energy level to that of gold nanoclusters.The feasibility of this method was verified by the agreement of the result with gold nanoclusters.This strategy was conductive to solving the blindness of reactive oxygen species screening in selective determination.