Determining surface chemical composition of silver nanoparticles during sulfidation by monitoring the ligand shell
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Evaluating the surface and core compositions of transforming nanoparticles (NP) represents a significant measurement challenge but is necessary for predicting performance in applied systems and their toxicity in natural environments. Here, we use X-ray photoelectron spectroscopy (XPS) and attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy to characterize both the surface and core of polyvinyl pyrollidone-silver nanoparticles in the presence of two Suwannee River fulvic acid (FA) standards and humic acid (HA) during sulfidation, the predominant transformation pathway in environmental systems. Only by using data from both spectroscopic methods was a clear relationship established between AgNP core composition and FA affinity established, where concomitant loss of FA was observed with Ag2S formation. Using XPS to measure AgNP surface composition, overlapping trends from XPS on FA I desorption from the AgNP surface as function of surface sulfidation were observed with FA II in the ATR-FTIR measurements. The reproducibility of the changing heterogeneous coating as a function of AgNP sulfidation provided a transferable method to determine the extent of Ag sulfidation without further need for the high resolution, high cost measurement tools that underpinned validation of the method. The relationship was not observed for HA, where a lower affinity to the AgNP surface was observed, suggesting distinct binding to the NP.
KeywordsTransformation Spectroscopy Natural organic matter Transferable methods Surface nanoscience
The authors thank Aaron Johnston-Peck for performing the TEM.
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Conflict of interest
The authors declare that they have no conflict of interest.
- Laborda F, Bolea E, Cepriá G, Gómez MT, Jiménez MS, Pérez-Arantegui J, Castillo JR (2016) Detection, characterization and quantification of inorganic engineered nanomaterials: a review of techniques and methodological approaches for the analysis of complex samples. Anal Chim Acta 904:10–32CrossRefGoogle Scholar
- Naumkin AV, Kraut-Vass A, Gaarenstroom SW, Powell CJ (2000) NIST X-ray photoelectron spectroscopy database. from NIST/Department of Commerce: https://srdata.nist.gov/xps/Default.aspx
- RM8017 (2016) Polyvinylpyrrolidone coated silver nanoparticles. National Institute of Standards and Technology; U.S. Department of Commerce: GaithersburgGoogle Scholar
- Zhang F, Allen AJ, Johnston-Peck AC, Liu J, Pettibone JM (2018) Transformation of engineered nanomaterials through the prism of silver sulfidation. Nanoscale Adv. https://doi.org/10.1039/C8NA00103K