Incorporation of Functionalized Palladium Nanoparticles within Ultrathin Nafion Films: A Nanostructured Composite for Electrolytic and Redox‐Mediated Hydrogen Evolution

Abstract

A novel ultrathin Nafion‐palladium nanocomposite film is developed by incorporating positively charged Pd nanoparticles, stabilized with dimethylaminopyridine (DMAP), into Nafion Langmuir‐Schaefer (LS) films. The films show considerable activity for the redox‐catalyzed hydrogen‐evolution reaction, the rate of which scales with film thickness. The Nafion film can be deposited on both insulating (glass) and electrode (indium‐tin oxide) surfaces. The quantity of Pd nanoparticles immobilized can be controlled simply via the thickness of the Nafion film. The morphology of the films are investigated using AFM, which allows the number density of nanoparticles to be estimated for the thinnest (10 layers; 18 nm) films. Incorporation of nanoparticles is also determined with cyclic voltammetry and UV‐visible spectroscopy. The former method allows estimation of the electrochemically active surface area of Pd wired to the underlying electrode. A novel scanning electrochemical microscopy (SECM) approach is used to investigate the kinetics of the hydrogen evolution reaction (HER) catalyzed by Pd nanoparticles within the Nafion film, which allows the intrinsic activity to be determined. Single nanoparticle reactivities are extracted and are comparable to the activity of native nanoparticles on glass and to bulk Pd. It is found that neither Nafion encapsulation nor DMAP functionalization impair the electrocatalytic activity of these nanoparticles towards the HER. Nafion encapsulation thus provides a framework for the formation of interfaces, whose activity scales with film thickness. The creation of 3D materials opens up the possibility of carrying out redox‐mediated hydrogen evolution using solution species as the electron donor.

Pd0@Polyoxometalate Nanostructures as Green Electrocatalysts: Illustrative Example of Hydrogen Production

“…Thus the exchange current density i 0 measured with Pd 0 @POM is 2 to 2.9 times larger than the corresponding value obtained for unmodified bulk Pd. A beneficial effect, but with a smaller enhancement, was also reported in the case of dimethylaminopyridine functionalized Pd nanoparticles [38]. The important outcome of the exchange current density measured in the present work is the confirmation that the presence of the POM has a beneficial effect on electrode activation as could be anticipated from recent work on POMs in the absence of noble metal [39].…”

Characterization of local electrocatalytical activity of nanosheet-structured ZnCo 2 O 4 /carbon nanotubes composite for oxygen reduction reaction with scanning electrochemical microscopy

“…The increasing interest on developing novel MTMOs hybrids as ORR catalyst candidates thus raises a new request on high throughput electrochemical screening methods with high spatial resolution and also providing local electrocatalytic activity information of the MTMOs catalysts. Scanning electrochemical microscopy (SECM), as a kind of scanning probe microscope with using a microelectrode as probe, can provide the local reactivity of sample with high spatial and temporal resolutions based on the recorded probe currents [28][29][30][31][32][33][34]. And since only small amount of sample needed in SECM experiment and its rapid experimental process, SECM has the capability of quickly and simultaneously evaluating reactivities of different catalysts within one single experiment.…”

Scanning Electrochemical Microscopy and Voltammetric Investigation of Silver Nanoparticles Embedded within a Nafion Membrane

“…Utilisation of the AgNPs for the abovementioned practical applications often requires the construction of integrated chemical systems, and in most cases polymer‐supported nanoparticles are employed . Among others, ion exchange membranes proved useful as supports for the fabrication of metal nanoparticles (NPs) . This is due to their unique morphology, having hydrophilic and hydrophobic nanodomains, which in principle allow nanoscale confinement of metallic deposits to be achieved.…”

“…[7] Amongo thers, ione xchange membranesp roved useful as supports fort he fabrication of metal nanoparticles (NPs). [8][9][10][11][12][13][14][15][16][17][18][19][20][21] Thisi sd ue to their unique morphology,h aving hydrophilic and hydrophobic nanodomains, which in principle allow nanoscale confinemento fm etallicd eposits to be achieved. Nafion is ap oly(perfluorosulfonic) acid membrane,k nown for its cation exchange properties as well as for its thermala nd chemical stability.…”