Catalytic Membrane Nanoreactor with Cu–Ag_x Bimetallic Nanoparticles Immobilized in Membrane Pores for Enhanced Catalytic Performance

Abstract

A catalytic membrane nanoreactor (CMNR) with Cu−Ag x (where x is the millimolar concentration of AgNO 3 ) bimetallic catalysts immobilized in membrane pores has been fabricated via coupling flowing synthesis and replacement reaction. Surface characterization by transmission electron microscopy (TEM) gives obvious evidence of the formation of Cu−Ag bimetallic core−shell nanostructures with Ag islands deposited on the Cu core metal. An apparent high shift phenomenon for the Cu element and a low shift phenomenon for the Ag element was determined by X-ray photoelectron spectroscopy (XPS), indicating a close interaction with the transfer of electron density from the Cu atom to the Ag atom. The hydrogenation catalysis of p-nitrophenol (p-NP) was tested to evaluate the catalytic performance. During the catalytic process, the Cu core acts as an electron-deficient site to adsorb and activate the −NO 2 group for p-NP, and the Ag shell is beneficial for enhancing active H spilling to the Cu surface and then performing hydrogenation. A volcano-shaped apparent reaction rate constant can be achieved, which rises initially with the increasing Ag content and subsequently drops with a further increase in the Ag content. The highest value of 1071 min −1 can be achieved for CMNR immobilized with Cu−Ag 2 owing to the suitable adsorption activation behavior and the best hydrogen spillover behavior.

Highly Nickel Loaded Nanocomposite Membranes for Catalytic H2 Production and Hydrogenation of p-Nitrophenol Using Ammonia Borane

“…In recent years, several new and advanced nonnoble metal catalysts were successfully synthesized with high catalytic activity. , Independent of the used metal, most fabrication methods rely on the presentation of the catalyst on a solid support, either as a template for the synthesis or to inhibit agglomeration in the solution . For the catalytic hydrogenation of p -NP, several studies already showed that adsorption, − particle anchoring, − metal coordination, ,− and electronic interactions ,− are possible synergistic effects between metal and support that can enhance the catalytic performance. This means that the optimization of the metal environment is an important factor to establish abundant nonnoble metals as effective catalysts.…”

3D‐Continuous Nanoporous Covalent Framework Membrane Nanoreactors with Quantitatively Loaded Ultrafine Pd Nanocatalysts

“…This approach combines the benefits of continuous flow chemistry and heterogeneous catalysis, offering a versatile methodology that enables control over fluid velocity and enhances mass transfer. [ 52–57 ] Figure 7b demonstrates the remarkable stability and performance of the PdNCF membrane nanoreactor, maintaining ≈96% conversion even after 100 h of continuous operation at a solution flux of ≈7.0 L m −2 h −1 , without any noticeable decline in activity. The extended stability is crucial for the PdNCF for continuous flow reactions.…”

Boosting Hydrogenation of Graphene Quantum Dot-Modified Photocatalysts: Specific Functionalized Modulation at Active Sites

“…27 These peaks shifted to lower binding energy levels after the deposition of PDDA, pGQDs, and rGQDs, indicating electron transfer from pGQDs/rGQDs to the HT framework. 36 Furthermore, the peaks belonging to −NH− of GQDs in the HT/PDDA/pGQDs and HT/PDDA/rGQD hybrid systems exhibited an obvious shift (about 0.4 and 0.1 eV, respectively) to higher binding energy levels compared with those of individual GQDs, and the signals corresponding to NH 4 + in PDDA in the hybrid systems just slightly shifted to higher binding energy levels compared with those of HT/PDDA NPs, 37 indicating strong electron interactions between GQDs and TiO 2 through the linking channel of the PDDA interlayer. 38 Photocatalytic Hydrogenation Performance of Various Catalysts.…”