Emphasis on the Properties of Metal‐Containing Zeolites Operating Outside the Comfort Zone of Current Heterogeneous Catalytic Reactions

Abstract

The development of catalysts that can operate under exceptionally harsh and unconventional conditions is of critical importance for the transition of the energy and chemicals industries to low‐emission and renewable chemical feedstocks. In this review we will highlight materials and more specifically metal‐containing zeolite catalysts that have been tested under harsh reaction conditions such as high temperature light alkane conversion and biomass valorization. Particular attention will be given to studies that explore the stability and recyclability of metal‐containing zeolite catalysts operating in continuous modes. Metal‐containing zeolites are considered as an important class of catalysts operating outside the comfort zone of current heterogeneous catalytic reactions in both gas and liquid phase reactions. The relationship between the properties of the metal‐containing zeolite and catalytic performance will be explored.

Altering the Atomic Order in Nanosized CHA Zeolites by Postsynthetic Silylation Treatment

“…Figure 3 presents the changes in the percentages of different Q [1][2][3][4] www.advsustainsys.com pH using variable Si concentrations. When 2 mmol g −1 of Si is inserted, all samples show a decrease in the amount of Q 1-2 species due to dealumination and an increase in the amount of Q [3][4] species due to silylation.…”

“…Zeolites are major players in petrochemical industries both for separation and catalysis thanks to their molecular-sized pore openings (0.3-2 nm) and shape selectivity. [1][2][3][4] Zeolites consist of ordered corner-sharing TO 4 tetrahedra (T = Si, Al) giving rise to a variety of framework topologies with tunable properties. [5,6] Synthetic zeolites are usually micrometer-sized polycrystalline powders exhibiting diffusion limitations due to the size of the micropores (0.3-2 nm) and crystals dimensions.…”

Catalytic Routes for Direct Methane Conversion to Hydrocarbons and Hydrogen: Current State and Opportunities

“…223 Recent reviews emphasize two disadvantages restricting the industrial development of the nonoxidative transformation of methane. 8,12,18,224 First, the MDA reaction is thermodynamically limited with a maximum of benzene conversion of 12.5% at 700 °C; thus the Mo/HZSM-5 catalysts shows low activity. Second, the coke formation at the high temperatures of the reaction is favored, leading to the fast deactivation of the catalyst and limiting the benzene selectivity.…”

Engineering RHO Nanozeolite: Controlling the Particle Morphology, Al and Cation Content, Stability, and Flexibility

“…Zeolites are microporous crystalline solids that play key roles in petrochemistry and consumer products, as well as possess significant potential in biomedical applications. − Their regular micropore networks allow for the selective adsorption and separation of molecules, providing size and shape-selective environments for acid- and base-catalyzed reactions. Nanozeolites offer several key advantages over conventional micron-sized zeolites such as a greater number of accessible active sites, more rapid diffusion of guest molecules, and a greater number of external silanol defects, which can be utilized for zeolite engineering. − However, only 25 of the 255 IZA registered frameworks have been prepared as nanozeolites and many syntheses involve the use of organic structure-directing agents (OSDAs), which are expensive and require a destructive removal by calcination generating NO x and CO x emissions.…”