Large-area synthesis of nanoscopic catalyst-decorated conductive MOF film using microfluidic-based solution shearing

Abstract

Conductive metal-organic framework (C-MOF) thin-films have a wide variety of potential applications in the field of electronics, sensors, and energy devices. The immobilization of various functional species within the pores of C-MOFs can further improve the performance and extend the potential applications of C-MOFs thin-films. However, there are currently no effective strategies for facile and scalable synthesis of high quality ultra-thin C-MOFs while simultaneously immobilizing functional species within the MOF pores. Here, we develop microfluidic channel-embedded solution-shearing (MiCS) for ultra-fast (≤ 5 mm/s) and large-area synthesis of high-quality nanocatalyst-embedded C-MOF thin-films with thickness controllability down to tens of nanometers. The MiCS method synthesizes nanoscopic catalyst-embedded C-MOF particles within the microfluidic channels, and simultaneously grows catalyst-embedded C-MOF thin-film uniformly over a large area using solution shearing. The thin-film displays highest nitrogen dioxide (NO2) sensing properties at room temperature in air amongst two-dimensional materials, owing to the high surface area and porosity of the ultra-thin C-MOFs, and the catalytic activity of the nanoscopic catalysts embedded in the C-MOFs. Therefore, our method, i.e. MiCS, can open new avenues of highly active and conductive porous materials for various applications.

Exceptional catalytic activity of oxygen evolution reaction via two-dimensional graphene multilayer confined metal-organic frameworks

“…The confinement environment endows the NiFe-MOF/G-2h electrode stabilized active sites, enhanced electrical conductivity and greatly reduced mass transport lengths. Laying the Fick's law side-by-side with the more comprehensive reports, one can indicate that the concentration of intermediates become gradient in the confinement environments during OER, which propels the intermediates from the center to the boundaries with abundant active sites 22,42,43 . More favorable electrocatalytic kinetic for NiFe-BTC//G can be demonstrated by the smaller Tafel slope of 55 mV dec −1 in comparison to bulk NiFe-BTC powder (189 mV dec −1 ), and commercial Ir/C//G (76 mV dec −1 ) and RuO 2 //G (103 mV dec −1 ) (Fig.…”

“…As such, the MOFs based electrodes usually suffer with low mass permeability 17,18 . A variety of methods have been proposed to solve these issues, such as the exfoliation of MOFs into ultrathin layers 19,20 , design of complicated linkers to obtain conductive MOFs [21][22][23][24][25] , carbonization of MOFs, and so on 26,27 . However, so far the electrocatalytic activities of MOF-based catalysts are still unsatisfied in comparison to state-of-the-art noble metal-based catalysts.…”

Inorganic microporous membranes for hydrogen separation: Challenges and solutions

“…Moreover, fast current-driven synthesis [100,101], microfluidic channel-embedded solution-shearing [102], supercritical fluids assistance [103] are newly emerging strategies for framework design or scaled-up manufacturing of MOF membranes.…”

Covalent transfer of chemical gradients onto a graphenic surface with 2D and 3D control

“…To investigate the concentration gradients forming over the HOPG substrate in the microfluidic device, we simulated the flow and mass transport in the microfluidic device using a computational fluid dynamics approach based on the finite volume method (in line with previous works simulating the flow and mass transport inside microfluidic devices) [37][38][39] . The steady-state velocity, pressure, and species concentration were calculated by coupling the Navier-Stokes equation for an incompressible Newtonian fluid, the continuity equation, and the species transport equation, which were respectively given by:…”