Reliable surface area determination of powders and meso/macroporous materials: Small-angle X-ray scattering and gas physisorption

Schlumberger, Carola; Scherdel, C.; Kriesten, Martin; Leicht, Peter; Keilbach, Andreas; Ehmann, Heike; Kotnik, Petra; Reichenauer, Gudrun; Thommes, Matthias

doi:10.1016/j.micromeso.2021.111554

Cited by 18 publications

(28 citation statements)

References 20 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Under certain carefully controlled conditions, the specific BET surface area of nonporous, macroporous, or mesoporous materials can be regarded as the probed accessible surface area. Details about surface area assessment with the BET method can be found elsewhere. ,, However, as already indicated in Section , a straightforward application of the BET theory for reliable surface area assessment is limited to materials which do not contain micropores. , The absence of microporosity is reflected in the argon/nitrogen adsorption isotherm shape. The BET method is valid for materials showing type II and type IV(a) adsorption isotherms according to the IUPAC classification .…”

Section: Resultsmentioning

confidence: 99%

“…Furthermore, reliable surface area assessment must be related to the right choice of adsorptive. As already discussed in Section , nitrogen adsorption can lead to an overestimation of the specific surface area due to specific interactions between nitrogen’s quadrupole moment and polar surface sites. , Argon adsorption at 87 K is recommended for surface area assessment by IUPAC because it does not show specific interactions with surface functional groups …”

Section: Resultsmentioning

confidence: 99%

“…Both methods are based on the comparison between the material under study and (nonporous) reference materials of comparable surface chemistry. However, small changes in the surface chemistry may have a stronger effect on surface area assessment by NMR relaxometry compared to surface area assessment by argon adsorption. ,, …”

Section: Methodsmentioning

confidence: 99%

“…Therefore, the orientation of the nitrogen molecule is very much dependent on the surface chemistry of the adsorbent. Hence, the effective cross-sectional area of nitrogen needed for the calculation of the surface area by the BET method depends on the surface chemistry, which may lead to uncertainties in assessing surface areas up to 20–25% for surfaces with polar surface functionality …”

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Reliable Surface Area Assessment of Wet and Dry Nonporous and Nanoporous Particles: Nuclear Magnetic Resonance Relaxometry and Gas Physisorption

et al. 2023

Self Cite

View full text Add to dashboard Cite

The reliable assessment of surface area is extremely important for many applications, e.g., catalysis, separation, and energy storage/conversion. Within this context, major progress has been made concerning the textural characterization of porous materials in the gas/dry state, e.g., gas physisorption and mercury porosimetry. However, these methods are not sufficient for the characterization of wet materials utilized in liquid-phase processes. For this, the application of nuclear magnetic resonance (NMR) relaxometry has been considered, but a systematic and rigorous assessment of the applicability of NMR relaxometry for reliable surface and pore size characterization of nanoporous materials is missing. Hence, we present a systematic study in which we assess the applicability of NMR relaxometry for reliable surface area assessment utilizing for the first time true surface area benchmark data based on argon 87 K adsorption on nonporous particles (silica and carbon black) coupled with the development of an advanced methodology including the investigation of the choice of the probe molecule and the effect of its accessibility to the pore network. Our results show that the method provides a fast (a few minutes per measurement) and reliable surface area of silica and carbon black model materials immersed in a liquid phase. In addition, our work clearly demonstrates the potential of NMR relaxometry for the targeted surface area assessment of defined pore classes (here ultramicropores) and suggests a new methodology for the characterization of pore entrances (pore window size). Furthermore, we investigate the effect of wettability and suggest that NMR relaxometry could be developed into a unique tool for assessing the wetting characteristics of adsorbate phases on pore surfaces. This fundamental study can be considered a first major step in enabling NMR relaxometry for reliable surface area assessment for wet materials, particularly relevant for materials used in processes occurring in a liquid phase.

show abstract

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Reliable Surface Area Assessment of Wet and Dry Nonporous and Nanoporous Particles: Nuclear Magnetic Resonance Relaxometry and Gas Physisorption

et al. 2023

Self Cite

View full text Add to dashboard Cite

show abstract

“…Furthermore, the USAXS/SAXS measurements were used to obtain structural information such as the shell thickness and the ring position, as shown in Figure 2. SAXS has been demonstrated to be a powerful technique to study porous material [34][35][36][37]. The principal peak positions q 1 at low q region for mSiO 2 /Pt-5.0/SiO 2 and Ring-mSiO 2 /Pt-5.0/SiO 2 are 0.169 Å −1 and 0.168 Å −1 , respectively.…”

Section: Surface Area Analysismentioning

confidence: 99%

Synthesis and Characterization of Mesoporous Silica Nanoparticles Loaded with Pt Catalysts

Lyu

Liu

et al. 2022

Catalysts

View full text Add to dashboard Cite

Coating the catalyst with a nanoporous layer has been demonstrated to be an effective approach to improve catalyst stability. Herein, we systematically investigate two types of core-shell mesoporous silica nanoparticles with a platinum nanocatalyst using a variety of characterization methods. One of the mesoporous particles has a unique amine ring structure in the middle of a shell (Ring-mSiO2/Pt-5.0/SiO2), and the other one has no ring structure (mSiO2/Pt-5.0/SiO2). Brunauer–Emmett–Teller/Barrett–Joyner–Halenda (BET/BJH) presented a similar surface area for both particles, and the pore size was 2.4 nm. Ultra-Small-Angle X-ray Scattering (USAXS)/ Small-Angle X-ray Scattering (SAXS) showed the size of mSiO2/Pt-5.0/SiO2 and Ring-mSiO2/Pt-5.0/SiO2 were 420 nm and 272 nm, respectively. It also showed that the ring structure was 30 nm above the silica core. Using high-resolution Transmission Electron Microscopy (TEM), it was found that the platinum nanoparticles are loaded evenly on the surface of the silica. In situ SAXS heating experiments and Thermogravimetric Analysis (TGA) indicated that the mSiO2/Pt-5.0/SiO2 were more stable during the high temperature, while the Ring-mSiO2/Pt-5.0/SiO2 had more change in the particle.

show abstract

Preparation and Surface Functionalization of a Tunable Porous System Featuring Stacked Spheres in Cylindrical Pores

Terlinden

Engelhardt

et al. 2023

Adv Materials Inter

Self Cite

View full text Add to dashboard Cite

A geometrically tunable nanoporous system featuring enhanced active surface area by stacking of spheres in cylindrical pores is fabricated. Highly ordered arrays of straight, constricted pores are obtained by anodization of metallic aluminum. Polystyrene (PS) spheres are assembled inside the pores by flowing their suspension through the porous membrane, whereas the construction serves as a filter. After surface functionalization with a noble metal catalyst, these model electrocatalysis systems exhibit functional properties (capacitance in electrochemical impedance spectroscopy) that mirror their geometric parameters. A systematic investigation of the system's geometry as it depends on the surface chemistry of the pores, on the one hand, and the physical parameters of the infiltration procedure, on the other hand, shows that mechanical stacking prevails over surface chemical interactions to determine the stacking density. The highest values of surface area are obtained when PS spheres are put in contact with HfO2 followed by ZnO according to adsorption measurements. Surface derivatization with organic layers does not improve stacking any further. However, choosing the proper concentration of PS spheres and flow rate are crucial for obtaining densely packed sphere assemblies without clogging of the pore entrance.

show abstract

Reliable surface area determination of powders and meso/macroporous materials: Small-angle X-ray scattering and gas physisorption

Cited by 18 publications

References 20 publications

Reliable Surface Area Assessment of Wet and Dry Nonporous and Nanoporous Particles: Nuclear Magnetic Resonance Relaxometry and Gas Physisorption

Reliable Surface Area Assessment of Wet and Dry Nonporous and Nanoporous Particles: Nuclear Magnetic Resonance Relaxometry and Gas Physisorption

Synthesis and Characterization of Mesoporous Silica Nanoparticles Loaded with Pt Catalysts

Preparation and Surface Functionalization of a Tunable Porous System Featuring Stacked Spheres in Cylindrical Pores

Contact Info

Product

Resources

About