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Title: AFM-IR and s-SNOM-IR measurements of chemically addressable monolayers on Au nanoparticles

Journal Article · · Journal of Chemical Physics
DOI:https://doi.org/10.1063/5.0072079· OSTI ID:1982363

The performance of catalysts depends on their nanoscale properties, and local variations in structure and composition can have a dramatic impact on the catalytic reactivity. Therefore, probing the localized reactivity of catalytic surfaces using high spatial resolution vibrational spectroscopy, such as infrared (IR) nanospectroscopy and tip-enhanced Raman spectroscopy, is essential for mapping their reactivity pattern. Two fundamentally different scanning probe IR nanospectroscopy techniques, namely, scattering-type scanning near-field optical microscopy (sSNOM) and atomic force microscopy-infrared spectroscopy (AFM-IR), provide the capabilities for mapping the reactivity pattern of catalytic surfaces with a spatial resolution of ~20 nm. Herein, we compare these two techniques with regard to their applicability for probing the vibrational signature of reactive molecules on catalytic nanoparticles. For this purpose, we use chemically addressable self-assembled molecules on Au nanoparticles as model systems. We identified significant spectral differences depending on the measurement technique, which originate from the fundamentally different working principles of the applied methods. While AFM-IR spectra provided information from all the molecules that were positioned underneath the tip, the s-SNOM spectra were more orientation-sensitive. Due to its field-enhancement factor, the s-SNOM spectra showed higher vibrational signals for dipoles that were perpendicularly oriented to the surface. The s-SNOM sensitivity to the molecular orientation influenced the amplitude, position, and signal-to-noise ratio of the collected spectra. Ensemble-based IR measurements verified that differences in the localized IR spectra stem from the enhanced sensitivity of s-SNOM measurements to the adsorption geometry of the probed molecules.

Research Organization:
Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States). Advanced Light Source (ALS)
Sponsoring Organization:
USDOE Office of Science (SC), Basic Energy Sciences (BES); European Research Council (ERC)
Grant/Contract Number:
AC02-05CH11231; 802769
OSTI ID:
1982363
Journal Information:
Journal of Chemical Physics, Vol. 155, Issue 20; ISSN 0021-9606
Publisher:
American Institute of Physics (AIP)Copyright Statement
Country of Publication:
United States
Language:
English

References (51)

Flexible NO 2 ‐Functionalized N‐Heterocyclic Carbene Monolayers on Au (111) Surface journal October 2019
Synchrotron infrared nano-spectroscopy and -imaging journal August 2020
Revealing Correlation of Valence State with Nanoporous Structure in Cobalt Catalyst Nanoparticles by In Situ Environmental TEM journal April 2012
Heterogeneities of individual catalyst particles in space and time as monitored by spectroscopy journal October 2012
Enhanced dielectric contrast in scattering-type scanning near-field optical microscopy journal August 2000
Studying birth, life and death of catalytic solids with operando spectroscopy journal April 2015
3D spectral imaging with synchrotron Fourier transform infrared spectro-microtomography journal August 2013
Infrared and Raman imaging of heterogeneous catalysts journal January 2010
On-surface photopolymerization of two-dimensional polymers ordered on the mesoscale journal June 2021
Analysis of nano-chemical mapping performed by an AFM-based (“AFMIR”) acousto-optic technique journal November 2007
Probing the surfaces of heterogeneous catalysts by in situ IR spectroscopy journal January 2010
Improved Method for the Preparation of Carboxylic Acid and Amine Terminated Self-Assembled Monolayers of Alkanethiolates journal March 2005
Infrared and Raman chemical imaging and spectroscopy at the nanoscale journal January 2020
In situ infrared monitoring of the solid/liquid catalyst interface during the three-phase hydrogenation of nitrobenzene over nanosized Au on TiO2 journal January 2011
High spatial resolution mapping of chemically-active self-assembled N-heterocyclic carbenes on Pt nanoparticles journal January 2016
Super-resolution imaging of non-fluorescent reactions via competition journal July 2019
Elucidating the Influence of Anchoring Geometry on the Reactivity of NO 2 -Functionalized N-Heterocyclic Carbene Monolayers journal August 2019
AFM-IR: Technology and Applications in Nanoscale Infrared Spectroscopy and Chemical Imaging journal December 2016
Organic Thiol Modified Pt/TiO 2 Catalysts to Control Chemoselective Hydrogenation of Substituted Nitroarenes journal August 2012
Nanoimaging of Orientational Defects in Semiconducting Organic Films journal April 2021
Operando chemistry of catalyst surfaces during catalysis journal January 2017
Site-dependent selectivity in oxidation reactions on single Pt nanoparticles journal January 2020
Molecular Sensitivity of Near-Field Vibrational Infrared Imaging journal September 2020
Site-Independent Hydrogenation Reactions on Oxide-Supported Au Nanoparticles Facilitated by Intraparticle Hydrogen Atom Diffusion journal July 2021
Theory of infrared nanospectroscopy by photothermal induced resonance journal June 2010
IR spectroscopy in catalysis journal July 2001
Infrared Imaging and Spectroscopy Beyond the Diffraction Limit journal July 2015
Revealing the Dynamics of Platinum Nanoparticle Catalysts on Carbon in Oxygen and Water Using Environmental TEM journal October 2017
Deactivation of Cu‐Exchanged Automotive‐Emission NH 3 ‐SCR Catalysts Elucidated with Nanoscale Resolution Using Scanning Transmission X‐ray Microscopy journal February 2020
Electrochemical deposition of N-heterocyclic carbene monolayers on metal surfaces journal November 2020
Copper catalysis at operando conditions—bridging the gap between single nanoparticle probing and catalyst-bed-averaging journal September 2020
Challenges and opportunities in IR nanospectroscopy measurements of energy materials journal April 2019
Uncovering the deactivation mechanism of Au catalyst with operando high spatial resolution IR and X-ray microspectroscopy measurements journal June 2016
High-spatial-resolution mapping of catalytic reactions on single particles journal January 2017
Nano-FTIR Absorption Spectroscopy of Molecular Fingerprints at 20 nm Spatial Resolution journal July 2012
Mapping Metals Incorporation of a Whole Single Catalyst Particle Using Element Specific X-ray Nanotomography journal January 2015
Ultrabroadband infrared nanospectroscopic imaging journal May 2014
Nanoscale chemical imaging of a working catalyst by scanning transmission X-ray microscopy journal November 2008
Apertureless near-field optical microscopy: Tip–sample coupling in elastic light scattering journal December 2003
In Situ IR and X-ray High Spatial-Resolution Microspectroscopy Measurements of Multistep Organic Transformation in Flow Microreactor Catalyzed by Au Nanoclusters journal February 2014
Watching in situ the hydrogen diffusion dynamics in magnesium on the nanoscale journal May 2020
Identifying Catalytic Reactions on Single Nanoparticles journal May 2018
Nano-optical imaging and spectroscopy of order, phases, and domains in complex solids journal December 2012
Spatial and temporal exploration of heterogeneous catalysts with synchrotron radiation journal August 2018
Influence of N-Substituents on the Adsorption Geometry of OH-Functionalized Chiral N-Heterocyclic Carbenes journal August 2021
Near-field microscopy by elastic light scattering from a tip
  • Keilmann, Fritz; Hillenbrand, Rainer
  • Philosophical Transactions of the Royal Society of London. Series A: Mathematical, Physical and Engineering Sciences, Vol. 362, Issue 1817 https://doi.org/10.1098/rsta.2003.1347
journal April 2004
Infrared Chemical Nano-Imaging: Accessing Structure, Coupling, and Dynamics on Molecular Length Scales journal March 2015
Functionalized Hydrogen-Bonding Self-Assembled Monolayers Grafted onto SiO2 Substrates journal December 2012
Identifying site-dependent reactivity in oxidation reactions on single Pt particles journal January 2018
In Situ/Operando Techniques for Characterization of Single-Atom Catalysts journal February 2019
Local infrared microspectroscopy with subwavelength spatial resolution with an atomic force microscope tip used as a photothermal sensor journal January 2005