Coating Process of Honeycomb Cordierite Support with Ni/Boehmite Gels

Abstract

This study presents the development of a method for the washcoating of Ni/boehmite gels, prepared by the sol–gel process, onto the surface of a commercial ceramic monolith. Indeed, a cordierite monolith in a honeycomb shape was used as the substrate for the Ni/Al2O3 deposition. An experimental assembly was made in order to apply the coating on the cordierite surface. Different suspensions were used with various viscosities, and multiple coating parameters were tested as the withdrawal speed, or the number of impregnations. It was observed that the simple deposition of the Ni/boehmite gel led to the formation of coating. Different morphologies were observed, and defects were highlighted as cracks, coating-free areas or aggregates. Among the various parameters studied, the pH of the sol appeared to play a role even more important than the viscosity. Indeed, the sol acidified with nitric acid showed a coating which was almost free of cracks or of large aggregates. Moreover, the use of a slurry mix of calcined alumina particles and colloidal boehmite appeared also as an interesting path. The beneficial influence of the slurry was attributed to a better resistance of the coating against the stresses induced during drying, and a deviation of the cracks in the gels by slurry grains.

Synthesis of tetrazoles catalyzed by a new and recoverable nanocatalyst of cobalt on modified boehmite NPs with 1,3-bis(pyridin-3-ylmethyl)thiourea

“…Because organic reactions take place at temperatures lower than the BNPs phase change. Therefore, Boehmite nanomaterials have also attracted attention in absorbent, 27 coatings, 28 flame retardant, 29 optical material, 30 ceramics, 31 vaccine adjuvants, 32 cosmetic products, 2,33 pillared clays and sweep-flocculation for fresh water treatment. 13 Consequently, we investigated a new complex of cobalt with 1,3-bis(pyridin-3-ylmethyl)thiourea on boehmite nanoparticle (Co-(PYT) 2 @BNPs) as a reusable nanocatalyst in the synthesis of tetrazole derivatives.…”

A New Neodymium Complex on Boehmite Nanoparticles with 1,3‐Bis(pyridine‐3‐ylmethyl)thiourea as a Practical and Reusable Nanocatalyst for the Chemoselective Synthesis of Tetrazoles

“…[12,45,46] Also, boehmite NPs have several unique properties e. g. great surface area, easy availability, non-toxicity, and mechanical and thermal stability. [12,47] Boehmite nanomaterials have also attracted considerable attention in absorbent, [48] coatings, [49] ceramics, [50] flame retardants, [51] vaccine adjuvants, [52] optical material, [53] cosmetic products [54] and starting material for the synthesis of alumina. [55] Therefore, in continuation of our previous work that samarium metal was stabilized on boehmite nanoparticles, [56] in this work, we introduced a new catalyst of neodymium on modified boehmite nanoparticle (Nd-bis(PYT)@boehmite NPs) as a practical, stable, reusable and stable nanocatalyst in the homoselective synthesis of 5-substituted-1H-tetrazole derivatives.…”

A new samarium complex of 1,3-bis(pyridin-3-ylmethyl)thiourea on boehmite nanoparticles as a practical and recyclable nanocatalyst for the selective synthesis of tetrazoles

“…In this sense, it is worth mentioning that boehmite nanomaterials can be employed as a support to stabilize several transition metals catalysts such as palladium 27 , nickel 28 , platinum 29 , molybdenum 30 , 31 , vanadium 31 , cobalt 32 , copper 33 , manganese 34 , iron 35 , rhodium 36 , ruthenium 37 and zirconium 28 . Boehmite nanomaterials have also attracted attention in coatings 38 , absorbents 39 , flame retardant 40 , ceramics 41 , optical materials 42 , vaccine adjuvants 43 , cosmetic products 32 and in synthesizing alumina as starting materials 44 . However, boehmite nanoparticles have some specific disadvantages (e.g.…”