Preparation of silicalite-1 layers on Pt-coated carbon materials: a possible electrochemical approach towards membrane reactors

Abstract

10A novel kind of composites is synthesized due to the outstanding properties of carbon materials. Metallic platinum is deposited 11 on porous carbon discs by means of Potential Step Deposition (PSD) under potentiostatic conditions. Afterwards, the Pt-coated 12 discs were covered completely with colloidal zeolite (silicalite-1) crystals by means of the novel Electro Phoretic Deposition 13 (EPD) methodology. After standard hydrothermal treatment, the seed crystal coating becomes continuous, crack-free and well-14 intergrown, giving rise to a layer of silicalite-1 crystals of different sizes. It must be noted that Pt combined with the secondary 15 growth methodology has a extremely important effect on the orientation of the growing zeolite crystals. These novel materials have 16 a wide range of potential applications as membrane reactors and/or catalyst membranes after activation (i.e. template removal by 17 calcination) of the zeolite crystals. 22As a direct consequence of the many applications of 23 crystalline zeolites, such as ion exchangers, adsorbents, 24 and molecular sieves fl], and all the possibilities implied 25 therein, increasing attention has been paid to preparing 26 zeolite membranes over the years [2], 27 Considering the many different strategies that have 28 been employed nowadays [3][4][5][6][7] and the wide variety of 29 supports that have been tested already , one might 30 think that the issue of preparing a supported zeolite 31 membrane has been successfully achieved. This, how-32 ever is not so, because even from the initial approach 33 of the direct treatment of the support with a zeolite pre-34 cursor solution [8]

NaA zeolite membranes on modified porous stainless steel supports: a comparative study of different SiO2 sources

“…Even though different methods have been reported for zeolite film deposition (Xu et al 2018), two routes are mainly used: in situ hydrothermal synthesis and secondary growth (Xu et al 2018). The latter, a two-step method, is more reproducible since it allows decoupling the nucleation and growth stages, improving the crystallization kinetics (Berenguer-Murcia et al 2005). Although many attempts have been made to improve zeolite deposition, there are several factors affecting the morphological, structural and physicochemical properties of the zeolite layer such as composition of the reactant mixture, temperature, raw materials and physical and chemical properties of the porous support (Feng et al 2015) that still need to be optimized.…”

Ordered Porous Nanomaterials: The Merit of Small

“…This includes the removal of heavy metals from soils and water streams [122,123] or the ability to bind pathogens in order to remove them from wastewater treatment plants, thus including sludge activity [124,125]. The outstanding relevance of zeolites is further illustrated by the number of reviews and research papers available in the literature covering topics as diverse as their use in catalysis (with reviews dating back to 1971 [126,127]), pollution control [128], electrochemistry (zeolites may act as electrode modifiers due to their ion-exchange and size selectivity capability) [129], photocatalysis [130], thin film technology for applications as membranes and electronic devices [131][132][133][134][135], or pharmaceutical applications [136].…”

Fabrication of AC@ZSM‐5 core‐shell particles and their performance in Fischer–Tropsch synthesis

“…To enhance zeolite adherence, modifications like air‐oxidation and chemical treatment were employed to increase the surface functional groups of the AC surface . Although the seeded growth method was introduced to obtain a membrane for carbon disks and carbon tubes, these methods proved unsuitable for depositing uniform seed layers on irregular millimeter‐sized AC particles.…”