Speciation of adsorbates on surface of solids by infrared spectroscopy and chemometrics

Vilmin, Franck; Bazin, Philippe; Thibault-Starzyk, Frédéric; Travert, Arnaud

doi:10.1016/j.aca.2015.06.006

Cited by 5 publications

(4 citation statements)

References 32 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…This technique, in which a microbalance is integrated with an FTIR in situ cell within a single set-up, allows simultaneous monitoring of the weight changes of the sample along with its IR spectra during adsorption or desorption of probe molecules, and consequently, highly accurate quantitative data, e.g. the molar absorption coefficient values, can be obtained directly, as demonstrated in [41][42][43]. In situ FTIR experiments.…”

Section: Introductionmentioning

confidence: 99%

Probing the acid sites of zeolites with pyridine: Quantitative AGIR measurements of the molar absorption coefficients

Zholobenko

Freitas

Jendrlin

et al. 2020

Journal of Catalysis

Self Cite

160

113

View full text Add to dashboard Cite

This study presents a detailed methodology, which combines high-precision thermogravimetry and FTIR spectroscopy, aiming to establish the most accurate and reliable means of measuring the molar absorption coefficients of adsorbed species. As the integrated molar absorption coefficients of Py complexes with Brønsted and Lewis acid sites, ɛ(Py-B) and ɛ(Py-L), are determined and the validity of the Beer-Lambert-Bouguer law for IR characterisation of solid acids is demonstrated, this work is setting a benchmark for the quantitative acidity measurements in zeolites and related materials. The following values of ɛ(Py-B) have been obtained at 150°C (band at ~1545 cm-1): 1.09±0.08 cm µmol-1 for ZSM-5; 1.12±0.16 cm µmol-1 for BEA; 1.29±0.04 cm µmol-1 for MOR and 1.54±0.15 cm µmol-1 for FAU. The value of ɛ(Py-L) (band at ~1455 cm-1 , which refers to different cations) measured at the same temperature is 1.71±0.1 cm µmol-1. Values of ɛ(Py-B) depend on the zeolite structure, in contrast to that for ɛ(Py-L). Clear correlations are presented between the temperature of the FTIR measurements and ɛ values for Py complexes and other species, which decrease by ~10% as the temperature increases by 100 o C. In addition, the effects of key experimental procedures, instrumentation design and sample preparation are established and quantified.

show abstract

Section: Introductionmentioning

confidence: 99%

Probing the acid sites of zeolites with pyridine: Quantitative AGIR measurements of the molar absorption coefficients

Zholobenko

Freitas

Jendrlin

et al. 2020

Journal of Catalysis

Self Cite

160

113

View full text Add to dashboard Cite

show abstract

“…Therefore, the desorption profile of *CO B at each V desorption , that is, IR peak area versus time, is acquired from the initial 60 s at V desorption to ensure correct quantification of *CO B desorption (Figure f). Here, we assume the surface concentration (Γ *CO B , the number of CO molecules adsorbed on bridge sites normalized to the geometric area of the Si//Au electrode) is proportional to the IR peak area ( A *CO B ) . The desorption profiles can be simply fitted by the first-order kinetics equation where k d is the rate constant, and Γ 0 ( A 0 ) refers to *CO B surface concentration (IR peak area) at t 0 moment.…”

Section: Resultsmentioning

confidence: 99%

“…Here, we assume the surface concentration (Γ *CO B , the number of CO molecules adsorbed on bridge sites normalized to the geometric area of the Si//Au electrode) is proportional to the IR peak area (A *CO B ). 72 The desorption profiles can be simply fitted by the first-order kinetics equation 73…”

Section: Resultsmentioning

confidence: 99%

Bridge Sites of Au Surfaces Are Active for Electrocatalytic CO₂ Reduction

et al. 2022

View full text Add to dashboard Cite

Prior in situ attenuated total reflectance Fourier transform infrared (ATR–FTIR) studies of electrochemical CO2 reduction catalyzed by Au, one of the most selective and active electrocatalysts to produce CO from CO2, suggest that the reaction proceeds solely on the top sites of the Au surface. This finding is worth updating with an improved spectroelectrochemical system where in situ IR measurements can be performed under real reaction conditions that yield high CO selectivity. Herein, we report the preparation of an Au-coated Si ATR crystal electrode with both high catalytic activity for CO2 reduction and strong surface enhancement of IR signals validated in the same spectroelectrochemical cell, which allows us to probe the adsorption and desorption behavior of bridge-bonded *CO species (*COB). We find that the Au surface restructures irreversibly to give an increased number of bridge sites for CO adsorption within the initial tens of seconds of CO2 reduction. By studying the potential-dependent desorption kinetics of *COB and quantifying the steady-state surface concentration of *COB under reaction conditions, we further show that *COB are active reaction intermediates for CO2 reduction to CO on this Au electrode. At medium overpotential, as high as 38% of the reaction occurs on the bridge sites.

show abstract

“…For short grafted chains (30 monomers per chain), below ϕ gft = 0.17 nm –2 , both the normalized brush height and the interpenetration width exhibit a plateau, as drawn in Figure S3. This first regime corresponds to the mushroom regime, ,, where the grafted polymer chains are far enough in order not to interact with each other. At ϕ gft = 0.17 nm –2 , the typical distance between two grafted polymer chain anchor points is = 24.5 Å, while the square root of the parallel component of the mean square radius of gyration of the grafted chains equals Å, meaning that the grafted chains start to feel each other.…”

Section: Resultsmentioning

confidence: 99%

Atomistic Descriptions of thecis-1,4-Polybutadiene/Silica Interfaces

Kempfer

Devémy

Dequidt

et al. 2019

ACS Appl. Polym. Mater.

View full text Add to dashboard Cite

Since the early 1940s, silica has been increasingly used in tire compounds as a complement to carbon blacks. The use of silica offers substantial benefits in tires, such as a low rolling resistance and a better grip on wet and icy roads. Nevertheless, coupling agents must be used to enable the mixing with rubber. The understanding of the action of silica in the reinforcement process and the role of the coupling agents at the molecular level requires the investigation of the interfacial region of the silica surface interacting with polymer chains. We report here detailed atomistic simulations of the interfacial region between different silica surfaces and cis-1,4-polybutadiene polymer chains. We describe the interfacial regions in terms of density and the radius of gyration component profiles along the normal to the substrate. We investigate how the nature of the silica surface, the surface density of silanols, and the surface coverage of grafted polymer chains and grafted OCTEO impact the molecular arrangements of the interfacial zone and the local properties of polymer chains.

show abstract

Speciation of adsorbates on surface of solids by infrared spectroscopy and chemometrics

Cited by 5 publications

References 32 publications

Probing the acid sites of zeolites with pyridine: Quantitative AGIR measurements of the molar absorption coefficients

Probing the acid sites of zeolites with pyridine: Quantitative AGIR measurements of the molar absorption coefficients

Bridge Sites of Au Surfaces Are Active for Electrocatalytic CO₂ Reduction

Atomistic Descriptions of thecis-1,4-Polybutadiene/Silica Interfaces

Contact Info

Product

Resources

About

Speciation of adsorbates on surface of solids by infrared spectroscopy and chemometrics

Cited by 5 publications

References 32 publications

Probing the acid sites of zeolites with pyridine: Quantitative AGIR measurements of the molar absorption coefficients

Probing the acid sites of zeolites with pyridine: Quantitative AGIR measurements of the molar absorption coefficients

Bridge Sites of Au Surfaces Are Active for Electrocatalytic CO2 Reduction

Atomistic Descriptions of thecis-1,4-Polybutadiene/Silica Interfaces

Contact Info

Product

Resources

About

Bridge Sites of Au Surfaces Are Active for Electrocatalytic CO₂ Reduction