Abstract
With the developments of near ambient pressure photoemission and the liquid microjet, X-ray photoelectron spectroscopy (XPS) measurements at the liquid-nanoparticle interface are now possible. This significant advance allows soft matter physicists working in the field of colloid nanoscience the opportunity to perform surface science experiments long deemed impossible. Here we use XPS in conjunction with a liquid microjet to study the electronic and geometric structures of a core–shell type nanoparticle, AlxOy@SiO2, suspended in aqueous solution. The Al 2p spectrum is consistent with two unique electronic structures that we assign to neutral sites, >Al–OH, at higher kinetic energy (KE) and to protonated species, >Al–OH2 +, at lower KE. The presence of excess positive charge on the nanoparticles surface is additionally confirmed by electrophoretic mobility experiments (positive zeta-potentials). Taking advantage of the quantitative nature of XPS we find ~35 % of the AlxOy monolayer is protonated at the pH of the experiment. Finally, we perform additional experiments as a function of photoelectron kinetic energy (depth profiling) and qualitatively determine the Si 2p/Al 2p ratios. We discuss the quantitative limitations to such an experiment in aqueous solution.
Similar content being viewed by others
References
Maeda K, Teramura K, Lu DL, Takata T, Saito N, Inoue Y, Domen K (2006) Photocatalyst releasing hydrogen from water—enhancing catalytic performance holds promise for hydrogen production by water splitting in sunlight. Nature 440(7082):295–395
Tedsree K, Li T, Jones S, Chan CWA, Yu KMK, Bagot PAJ, Marquis EA, Smith GDW, Tsang SCE (2011) Hydrogen production from formic acid decomposition at room temperature using a Ag–Pd core–shell nanocatalyst. Nat Nanotechnol 6(5):302–307
Ung T, Liz-Marzan LM, Mulvaney P (1998) Controlled method for silica coating of silver colloids. Influence of coating on the rate of chemical reactions. Langmuir 14(14):3740–3748
Maliakal A, Katz H, Cotts PM, Subramoney S, Mirau P (2005) Inorganic oxide core, polymer shell nanocomposite as a high K gate dielectric for flexible electronics applications. J Am Chem Soc 127(42):14655–14662
Wu WT, Zhou T, Berliner A, Banerjee P, Zhou SQ (2010) Smart core–shell hybrid nanogels with Ag nanoparticle core for cancer cell imaging and gel shell for pH-regulated drug delivery. Chem Mater 22(6):1966–1976
Pinaud F, Michalet X, Bentolila LA, Tsay JM, Doose S, Li JJ, Iyer G, Weiss S (2006) Advances in fluorescence imaging with quantum dot bio-probes. Biomaterials 27(9):1679–1687
Schartl W (2000) Crosslinked spherical nanoparticles with core–shell topology. Adv Mater 12(24):1899–1908
Soppimath KS, Tan DCW, Yang YY (2005) pH-triggered thermally responsive polymer core–shell nanoparticles for drug delivery. Adv Mater 17(3):318–323
Lee WR, Kim MG, Choi JR, Park JI, Ko SJ, Oh SJ, Cheon J (2005) Redox-transmetalation process as a generalized synthetic strategy for core–shell magnetic nanoparticles. J Am Chem Soc 127(46):16090–16097
Rupprechter G, Weilach C (2007) Mind the gap! Spectroscopy of catalytically active phases. Nano Today 2(4):20–29
Tao F, Zhang SR, Nguyen L, Zhang XQ (2012) Action of bimetallic nanocatalysts under reaction conditions and during catalysis: evolution of chemistry from high vacuum conditions to reaction conditions. Chem Soc Rev 41(24):7980–7993
Blomberg S, Hoffmann MJ, Gustafson J, Martin NM, Fernandes VR, Borg A, Liu Z, Chang R, Matera S, Reuter K, Lundgren E (2013) In situ X-ray photoelectron spectroscopy of model catalysts: at the edge of the gap. Phys Rev Lett 110(11):117601
Arrigo R, Havecker M, Schuster ME, Ranjan C, Stotz E, Knop-Gericke A, Schlogl R (2013) In situ study of the gas-phase electrolysis of water on platinum by NAP-XPS. Angew Chem Int Ed 52(44):11660–11664
Ghosal S, Hemminger JC, Bluhm H, Mun BS, Hebenstreit ELD, Ketteler G, Ogletree DF, Requejo FG, Salmeron M (2005) Electron spectroscopy of aqueous solution interfaces reveals surface enhancement of halides. Science 307(5709):563–566
Brown MA, D’Auria R, Kuo IFW, Krisch MJ, Starr DE, Bluhm H, Tobias DJ, Hemminger JC (2008) Ion spatial distributions at the liquid–vapor interface of aqueous potassium fluoride solutions. Phys Chem Chem Phys 10(32):4778–4784
Starr DE, Pan D, Newberg JT, Ammann M, Wang EG, Michaelides A, Bluhm H (2011) Acetone adsorption on ice investigated by X-ray spectroscopy and density functional theory. Phys Chem Chem Phys 13(44):19988–19996
Krepelova A, Bartels-Rausch T, Brown MA, Bluhm H, Ammann M (2013) Adsorption of acetic acid on ice studied by ambient-pressure XPS and partial-electron-yield NEXAFS spectroscopy at 230–240 K. J Phys Chem A 117(2):401–409
Tao F, Grass ME, Zhang YW, Butcher DR, Renzas JR, Liu Z, Chung JY, Mun BS, Salmeron M, Somorjai GA (2008) Reaction-driven restructuring of Rh–Pd and Pt–Pd core–shell nanoparticles. Science 322(5903):932–934
Tao F, Grass ME, Zhang YW, Butcher DR, Aksoy F, Aloni S, Altoe V, Alayoglu S, Renzas JR, Tsung CK, Zhu ZW, Liu Z, Salmeron M, Somorjai GA (2010) Evolution of structure and chemistry of bimetallic nanoparticle catalysts under reaction conditions. J Am Chem Soc 132(25):8697–8703
Alayoglu S, Tao F, Altoe V, Specht C, Zhu ZW, Aksoy F, Butcher DR, Renzas RJ, Liu Z, Somorjai GA (2011) Surface composition and catalytic evolution of Au (x) Pd1−x (x = 0.25, 0.50 and 0.75) nanoparticles under CO/O2 reaction in torr pressure regime and at 200 °C. Catal Lett 141(5):633–640
Uemura Y, Inada Y, Bando KK, Sasaki T, Kamiuchi N, Eguchi K, Yagishita A, Nomura M, Tada M, Iwasawa Y (2011) Core–shell phase separation and structural transformation of Pt3Sn alloy nanoparticles supported on gamma-Al2O3 in the reduction and oxidation processes characterized by in situ time-resolved XAFS. J Phys Chem C 115(13):5823–5833
Mu RT, Fu Q, Liu HY, Tan DL, Zhai RS, Bao XH (2009) Reversible surface structural changes in Pt-based bimetallic nanoparticles during oxidation and reduction cycles. Appl Surf Sci 255(16):7296–7301
Papaefthimiou V, Dintzer T, Dupuis V, Tamion A, Tournus F, Teschner D, Havecker M, Knop-Gericke A, Schlogl R, Zafeiratos S (2011) When a metastable oxide stabilizes at the nanoscale: wurtzite CoO formation upon dealloying of PtCo nanoparticles. J Phys Chem Lett 2(8):900–904
Piccinin S, Zafeiratos S, Stampfl C, Hansen TW, Havecker M, Teschner D, Bukhtiyarov VI, Girgsdies F, Knop-Gericke A, Schlogl R, Scheffler M (2010) Alloy catalyst in a reactive environment: the example of Ag–Cu particles for ethylene epoxidation. Phys Rev Lett 104(3):035503
Parks GA (1965) The isoelectric points of solid oxides solid hydroxides and aqueous hydroxo complex systems. Chem Rev 65(2):177–198
Brown MA, Beloqui Redondo A, Jordan I, Duyckaerts N, Lee TM, Ammann M, Nolting F, Kleibert A, Machler JP, Birrer M, Wörner HJ, van Bokhoven JA (2013) A new endstation at the Swiss light source for ultraviolet photoelectron spectroscopy, X-ray photoelectron spectroscopy, and X-ray absorption spectroscopy measurements of liquid solutions. Rev Sci Instrum 84:073904
Flechsig U, Nolting F, Rodriguez AF, Krempasky J, Quitmann C, Schmidt T, Spielmann S, Zimoch D (2010) Performance measurements at the SLS SIM beamline. AIP Conf Proc 1234:319–322
Brown MA, Jordan I, Beloqui Redondo A, Kleibert A, Wörner HJ, van Bokhoven JA (2013) In situ photoelectron spectroscopy at the liquid/nanoparticle interface. Surf Sci 610:1–6
Brown MA, Arrigoni M, Heroguel F, Beloqui Redondo A, Giordano L, van Bokhoven JA, Pacchioni G (2014) pH dependent electronic and geometric structures at the water–silica nanoparticle interface. J Phys Chem C 118(50):29007–29016
Shaw DJ (1992) Introduction to colloid and surface chemistry, 4th edn. Butterworth-Heinemann Ltd., Oxford
Yeh JJ, Lindau I (1985) Atomic subshell photoionization cross-sections and asymmetry parameters—1 less-than-or-equal-to Z less-than-or-equal-to 103. Atom Data Nucl Data 32(1):1–155
Brown MA, Huthwelker T, Beloqui Redondo A, Janousch M, Faubel M, Arrell CA, Scarongella M, Chergui M, van Bokhoven JA (2012) Changes in the silanol protonation state measured in situ at the silica–aqueous interface. J Phys Chem Lett 3(2):231–235
Brown MA, Beloqui Redondo A, Sterrer M, Winter B, Pacchioni G, Abbas Z, van Bokhoven JA (2013) Measure of surface potential at the aqueous–oxide nanoparticle interface by XPS from a liquid microjet. Nano Lett 13(11):5403–5407
Beloqui Redondo A, Jordan I, Ziazadeh I, Kleibert A, Giorgi JB, Wörner HJ, May S, Abbas Z (2015) Nanoparticle induced charge redistribution of the air–water interface. J Phys Chem C 119(5):2661–2668
Brown MA, Duyckaerts N, Beloqui Redondo A, Jordan I, Nolting F, Kleibert A, Ammann M, Wörner HJ, van Bokhoven JA, Abbas Z (2013) Effect of surface charge density on the affinity of oxide nanoparticles for the vapor–water interface. Langmuir 29(16):5023–5029
Lagström T, Gmür TA, Quaroni L, Goel A, Brown MA (2015) Surface vibrational structure of colloidal silica and its direct correlation with surface charge density. Langmuir 31:3621–3626
Brown MA, Seidel R, Thurmer S, Faubel M, Hemminger JC, van Bokhoven JA, Winter B, Sterrer M (2011) Electronic structure of sub-10 nm colloidal silica nanoparticles measured by in situ photoelectron spectroscopy at the aqueous–solid interface. Phys Chem Chem Phys 13(28):12720–12723
Iler RK (1979) The chemistry of silica: solubility, polymerization, colloid and surface properties and biochemistry of silica. Wiley, New York
Lyklema J (1995) Fundamentals of interface and colloid science, vol II: Solid–liquid interfaces. Academic Press Inc., San Diego
Crist BV (2005) Handbooks of monochromatic XPS spectra—volume 2—commercially pure binary oxides. XPS International, LLC, Mountain View
Jordan I, Beloqui Redondo A, Brown MA, Fodor D, Staniuk M, Kleibert A, Wörner HJ, Giorgi JB, van Bokhoven JA (2014) Non-uniform spatial distribution of tin oxide (SnO2) nanoparticles at the air–water interface. Chem Commun 50(32):4242–4244
Suzuki YI, Nishizawa K, Kurahashi N, Suzuki T (2014) Effective attenuation length of an electron in liquid water between 10 and 600 eV. Phys Rev E 90(1):010302
Thurmer S, Seidel R, Faubel M, Eberhardt W, Hemminger JC, Bradforth SE, Winter B (2013) Photoelectron angular distributions from liquid water: effects of electron scattering. Phys Rev Lett 111(17):173005
Gehring T, Fischer TM (2011) Diffusion of nanoparticles at an air/water interface is not invariant under a reversal of the particle charge. J Phys Chem C 115(48):23677–23681
Shrestha A, Bohinc K, May S (2012) Immersion depth of positively versus negatively charged nanoparticles at the air–water interface: a Poisson–Boltzmann model. Langmuir 28(40):14301–14307
Acknowledgments
Portions of this work were performed at the SIM bealine of the Swiss Light Source, Paul Scherrer Institute. The NAPP endstation is supported by the Swiss National Science Foundation (No. 139139) and PSI FoKo. G.O. acknowledges funding from ETH (ETH-20 13-2). The authors are indebted to the staff of the SIM beamline, in particular Armin Kleibert, for their technical assistance. Prof. Nicholas D. Spencer and the LSST group are acknowledged for support and Prof. Javier B. Giorgi for fruitful discussions. A. Beloqui Redondo, I. Jordan, N. Duyckaerts, M.-T. Lee, M. Ammann, J. van Bokhoven, M. Birrer, J.-P. Mächler and F. Nolting are acknowledged for their help at the beamline during the initial stages of this project.
Author information
Authors and Affiliations
Corresponding author
Rights and permissions
About this article
Cite this article
Olivieri, G., Brown, M.A. Structure of a Core–Shell Type Colloid Nanoparticle in Aqueous Solution Studied by XPS from a Liquid Microjet. Top Catal 59, 621–627 (2016). https://doi.org/10.1007/s11244-015-0517-3
Published:
Issue Date:
DOI: https://doi.org/10.1007/s11244-015-0517-3