Phosphatation of zeolite H-ZSM-5: a combined microscopy and spectroscopy study.

A variety of phosphated zeolite H-ZSM-5 samples are investigated by using a combination of Fourier transfer infrared (FTIR) spectroscopy, single pulse (27)Al, (29)Si, (31)P, (1)H-(31)P cross polarization (CP), (27)Al-(31)P CP, and (27)Al 3Q magic angle spinning nuclear magnetic resonance (MAS NMR) spectroscopy, scanning transmission X-ray microscopy (STXM) and N2 physisorption. This approach leads to insights into the physicochemical processes that take place during phosphatation. Direct phosphatation of H-ZSM-5 promotes zeolite aggregation, as phosphorus does not penetrate deep into the zeolite material and is mostly found on and close to the outer surface of the zeolite, acting as a glue.

Large zeolite H-ZSM-5 crystals as models for the methanol-to-hydrocarbons process: bridging the gap between single-particle examination and bulk catalyst analysis.

The catalytic, deactivation, and regeneration characteristics of large coffin-shaped H-ZSM-5 crystals were investigated during the methanol-to-hydrocarbons (MTH) reaction at 350 and 500 °C. Online gas-phase effluent analysis and examination of retained material thereof were used to explore the bulk properties of large coffin-shaped zeolite H-ZSM-5 crystals in a fixed-bed reactor to introduce them as model catalysts for the MTH reaction. These findings were related to observations made at the individual particle level by using polarization-dependent UV-visible microspectroscopy and mass spectrometric techniques after reaction in an in situ microspectroscopy reaction cell.

3D nanoscale chemical imaging of the distribution of aluminum coordination environments in zeolites with soft X-ray microscopy.

Which side are you on? Scanning transmission X-ray microscopy is used for the first time to elucidate the coordination and distribution of aluminum in industrial-relevant zeolites at the single-particle level. Extended regions of a few hundred nanometers, rich in higher aluminum coordination environments, are heterogeneously embedded within the zeolite particle, before and after a steaming post-treatment.

Styrene oligomerization as a molecular probe reaction for Brønsted acidity at the nanoscale.

The Brønsted acid-catalyzed oligomerization of 4-fluorostyrene has been studied on a series of H-ZSM-5 zeolite powders, steamed under different conditions, with a combination of UV-Vis micro-spectroscopy and Scanning Transmission X-ray Microscopy (STXM). UV-Vis micro-spectroscopy and STXM have been used to monitor the relative formation of cyclic and linear dimeric carbocations as a function of the steaming post-treatment (i.e.

The porosity, acidity, and reactivity of dealuminated zeolite ZSM-5 at the single particle level: the influence of the zeolite architecture.

A combination of atomic force microscopy (AFM), high-resolution scanning electron microscopy (HR-SEM), focused-ion-beam scanning electron microscopy (FIB-SEM), X-ray photoelectron spectroscopy (XPS), confocal fluorescence microscopy (CFM), and UV/Vis and synchrotron-based IR microspectroscopy was used to investigate the dealumination processes of zeolite ZSM-5 at the individual crystal level. It was shown that steaming has a significant impact on the porosity, acidity, and reactivity of the zeolite materials. The catalytic performance, tested by the styrene oligomerization and methanol-to-olefin reactions, led to the conclusion that mild steaming conditions resulted in greatly enhanced acidity and reactivity of dealuminated zeolite ZSM-5.

In-situ scanning transmission X-ray microscopy of catalytic solids and related nanomaterials.

The present status of in-situ scanning transmission X-ray microscopy (STXM) is reviewed, with an emphasis on the abilities of the STXM technique in comparison with electron microscopy. The experimental aspects and interpretation of X-ray absorption spectroscopy (XAS) are briefly introduced and the experimental boundary conditions that determine the potential applications for in-situ XAS and in-situ STXM studies are discussed. Nanoscale chemical imaging of catalysts under working conditions is outlined using cobalt and iron Fischer-Tropsch catalysts as showcases.