Tag: electron diffraction

Users of ALBA create the most porous zeolite to date

Users of ALBA create the most porous zeolite to date

A team from the Materials Science Institute of Madrid -CSIC) leads an international research that synthetized a zeolite with extra-large pores by expanding and connecting silica chains. This material has applications in water and gas decontamination and catalysis. Experiments carried out at the MSPD beamline of the ALBA Synchrotron had a key role in determining the structure of the zeolite.

A team from the Materials Science Institute of Madrid (ICMM-CSIC) leads an international research that has succeeded in creating the world’s most porous zeolite. The study, published yesterday in the journal Nature, opens up new avenues for water and gas decontamination and “demonstrates that it is possible to make more porous materials that are stable,” says Miguel Camblor, researcher at the ICMM-CSIC and lead author of the study.

Zeolites are microporous crystalline silicates. These are materials with applications in decontamination, catalysis, gas adsorption, and cation exchange. For decades, obtaining stable zeolites with greater porosity and, therefore, capacity for absorption and processing of large molecules, has been an important scientific goal. However, this is not a simple challenge: “until recently, it challenged our synthetic capacity,” indicates Camblor.

The team already developed in recent years two zeolites with “extra-large” pores in the three spatial directions that also exhibited high stability. On this occasion, they have created a stable aluminosilicate zeolite with extra-large pores open through rings of more than 12 tetrahedra, capable of processing even larger molecules.

“The structure of this zeolite presents unprecedented characteristics and demonstrates that with different methods, things that were believed impossible can be found, such as this world record in porosity,” highlights Camblor, who indicates that they have already used the zeolite for the absorption of volatile organic compounds.

To determine the structure of the zeolite, the research team has combined electron diffraction techniques and powder X-ray diffraction, the latter available at the MSPD beamline of the ALBA Synchrotron. The X-rays produced at the ALBA’s accelerator provided crucial information on the position of the atoms in the zeolite structure.

Read more on the ALBA website

Image: Structure of the zeolite called ZEO-5

Credit: Nature

Promising new extra-large pore zeolite

Promising new extra-large pore zeolite

An international research team, led in Spain by CSIC scientist Miguel A. Camblor, has discovered a stable aluminosilicate zeolite with a three dimensional system of interconnected extra-large pores, named ZEO-1.

Zeolites are crystalline porous materials with important industrial applications, including uses in catalytic processes. The pore apertures limit the access of molecules into and out of the inner confined space of zeolites, where reactions occur.

The research, published in Science, proved that ZEO-1 possesses these “extra-large” pores of around 10 Å (1 angstrom equals one ten billionth of a meter), but also smaller pores of around 7 Å, which is actually the size of traditional “large” pores.

Because of its porosity, strong acidity and high stability, ZEO-1 may find applications as a catalyst in fine chemistry for the production of pharmaceutical intermediates, in controlled substance release, for pollution abatement or as a support for the encapsulation of photo- or electroactive species (they react to light or an electric field).

“The crossings of its cages delimit super boxes, open spaces that can be considered nanoreactors to carry out chemical reactions in their confined space”, explains Miguel A. Camblor, researcher at the Instituto de Ciencia de Materiales de Madrid – CSIC.

To prove that this new zeolite may be useful in applications involving bigger molecules, researchers measured the adsorption to the inner surface of the zeolite of the dye Nile red – a big molecule. Moreover, they tested its performance in fluid catalytic cracking of heavy oil, a process the world still relies on to produce fuels. In both processes, the new zeolite performed better than the conventional large pore zeolite used nowadays.

This research is the result of an international collaboration between eight research centers in China, the USA, Sweden and Spain. The team was led by Fei-Jian Chen (Bengbu Medical College, China), Xiaobo Chen (China University of Petroleum), Jian Li (Stockholm University) and Miguel A. Camblor (Instituto de Ciencia de Materiales de Madrid, CSIC).

Structure determination with synchrotron light

The zeolite was discovered following a high-throughput screening methodology. The structure solution was challenging because the zeolite has a very complex structure, with a small crystal size (<200nm) but an exceedingly large cell volume.

“The combination of electron diffraction data with synchrotron powder X-ray diffraction data collected at the MSPD beamline of the ALBA Synchrotron and the Argonne National Laboratory (USA) made possible the accurate structure determination of ZEO-1″, says Camblor.

Read more on the ALBA website

Image: A perspective view of the extra-large pore of ZEO-1 along (100)