Heterogeneous catalyst engineering ⇒ from stable and deactivation resistant to viable technical catalyst

Problem statement

Advances in heterogeneous catalyst “structure” are driven to improve their “function” or performance, i.e., activity, selectivity, and stability. Cooperative research is required to understand the structure and function relationships: developing new synthesis protocols for heterogeneous catalysts with unique surface properties, defined porosity, identification and understanding of catalytically active sites, reaction mechanisms, and finally, prediction and analysis of the processes using various computational tools.

Our group focuses on developing new catalyst formulations using innovative synthesis routes for various important heterogeneous catalysts. That includes thermal, electro, and bio-electro catalysis.

The active phase cannot be used directly in its final application or reactor for various reasons, including poor mechanical resistance, heat or mass transport, and fluidization features. We must mix the active phase with other ingredients in a matrix of binder and filler, while we shape it into a technical catalyst. We investigate new synthetic protocols for technical catalysis using spray drying and fluidized beds to cover the whole range of sizes. At the same time, we incorporate additional (unconventional) ingredients such as SiC to improve some features even further.

Goals

  • Technical catalyst I ⇒ spray drying and extrusion
  • Technical catalyst II ⇒ spray fluidized bed reactor
  • Technical catalyst III ⇒ electrospinning
  • Zeolite catalysts ⇒ with defined structure/porosity
  • Multi-metal (high entropy) alloy catalysts
  • MXene catalysts ⇒ single and multi-dimensional
  • Perovskite catalysts
  • Metal-organic framework (MOFs) catalysts
  • Supported metal/metal-oxide catalysts
  • Aerogel catalyst

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Related Covers

Related Publications

Differences among the Deactivation Pathway of HZSM-5 Zeolite and SAPO-34 in the Transformation of Ethylene or 1-Butene to Propylene

by Epelde, Ibanez, Aguayo, Gayubo, Bilbao, Castaño
Micorp. Mesopor. Mat. Year: 2014

Abstract

The deactivation of HZMS-5 and SAPO-34 catalysts has been studied in the transformation of ethylene and 1-butene under propylene intensification conditions. The deterioration of spent catalysts’ physical properties have been quantified and coke has been characterized by TPO and by several spectroscopic techniques (Raman, 13C NMR, FTIR, FTIR-TPO), in order to determine the effect reaction medium composition and the severity of catalyst shape selectivity have on the nature and location of the coke in the porous structure. The results reveal that the mechanism for coke deactivation consists of two steps: one for the formation of alkylated aromatics by oligomerization and another for the coke growth-condensation. The first step is analogous for both catalysts and it principally depends on the catalyst acid strength and acid site density. The second step is different for both catalysts: the microporous structure of SAPO-34, with cavities in the intersections, inhibits the diffusion of alkylated aromatics towards the outside of the structure, thus blocking active acid sites; whereas, HZSM-5 structure, with a high connectivity and without cavities, favors the diffusion of the aromatics that evolve for a longer time outside of the micropores. At process conditions, the results demonstrate that the coke formation is faster from ethylene than from 1-butene, due to the lower reactivity of ethylene for oligomerization-cracking mechanisms as well as its higher capability for coke formation.

Keywords

HCE OLG