Preparation of a Catalyst Layer by Layer-by-Layer Self-Assembly for Plate-Type Catalytic Membrane Microreactors

Abstract

Benefiting from the structures of membrane and microchannel, catalytic membrane microreactors are attractive for multiphase catalytic reactions. In addition to the membrane development, the fabrication of an efficient catalyst layer on a supporting layer is also significant for improving the performance of the membrane microreactor. In the present study, a plate-type catalytic membrane microreactor with the catalyst layer prepared by the layer-by-layer self-assembly technology along with the in situ adsorption and reduction was proposed. Herein, polydopamine (PDA) and polyelectrolyte multilayers (PEMs) were coated on the surface of the polydimethylsiloxane supporting membrane to adsorb more PdCl 4 2− ions for the subsequent reduction. The synthesized catalyst layer termed as PDA/PEMs/Pd was characterized by analyzing the chemical composition and surface morphology. In addition, the catalytic performance of the developed microreactor was tested by using hydrogenation of nitrobenzene. The results showed that the use of both PDA and PEMs for preparing the catlayst layer yielded better conversion and durability than the use of PDA or PEMs alone. Besides, the nitrobenzene solution flow rate had an adverse impact of the nitrobenzene conversion resulting from the decreased residence time. With the increase of the hydrogen flow rate, the nitrobenzene conversion could be improved due to the increased gas permeation. The nirobenzene conversion also increased with a reduction in the initial concentration of nitrobenzene. In short, employing the layer-by-layer self-assembly technology for the catalyst layer preparation is promising for catalytic membrane microreactors toward multiphase catalytic reactions.

Towards Heterogeneous Catalysis: A Review on Recent Advances of Depositing Nanocatalysts in Continuous–Flow Microreactors

“…Finally, a charged surface that was ideal for metal ion adsorption and metal nanoparticle anchoring was formed. Liu et al [74] designed a plate-type catalytic membrane microreactor and prepared palladium nanocatalysts on a PEM-functionalized polydimethylsiloxane membrane. The obtained catalyst layer also showed excellent performance for NB conversion.…”

Construction of Microreactor-like Square-Hole Carbon Nitride Boosting Photocatalytic Nitrogen Fixation Activity

“…Therefore, enhanced mass transfer is one of the key means to promote performance. To achieve this, the use of microreactors with high mass transfer efficiency has become widely adopted in the fields of chemistry and materials synthesis. − In a microreactor, the reduction of reaction space increases the degree of turbulence while reducing diffusion resistance, and mixing is enhanced. On the other hand, the microreactor facilitates the formation of a stable bubble flow and increases the resistance time, ensuring sufficient reaction time for the gas and the active centers on the solids.…”

Development of Nanolayer Blown Film Technology

“…Many methodologies have been developed to produce nanolayer films so far, including layer-by-layer multilayers from polymer solutions or melts, , self-assembly of block copolymers, and the cast film of nanolayer coextrusion . Among them, the cast film of nanolayer coextrusion has attracted great attention in the scientific community due to its scalability, solvent-free nature, and cost-efficiency. ,, The cast film of nanolayer coextrusion includes nanolayer coextrusion and cast die, two main parts.…”

“…Academic research on nanolayer films can be broadly summarized into three aspects: (i) interfacial phenomena: the two-dimensional (2D) interfacial region takes a considerable, even a predominate ratio out of the bulk of nanolayer films, which is valuable to study the interfacial phenomena including interfacial diffusion, 10,11 interfacial reaction, 12,51 interfacial epitaxial crystallization, 13,14,50 interfacial slip 15 and instabilities during flow, 11 interfacial adhesion and debonding, 16 and so on; (ii) confined phase transition and molecular relaxation behaviors: the confined layer space generated by the alternating nanolayer in the nanolayer film can be used to study the confined phase transitions such as confined crystallization, 17,18 confined glass transition, 19 and confined phase separation, 20 as well as the confined damping and confined chain relaxation; 21 and (iii) unequaled performances conferred by the superlattice nanolayer configuration such as advanced optical performances 22,23 and outstanding mechanical and gas barrier performance. 3 Many methodologies have been developed to produce nanolayer films so far, including layer-by-layer multilayers from polymer solutions or melts, 3,24 self-assembly of block copolymers, 25 and the cast film of nanolayer coextrusion. 26 Among them, the cast film of nanolayer coextrusion has attracted great attention in the scientific community due to its scalability, solvent-free nature, and cost-efficiency.…”