Studi di trasferimento di carica ad interfacce

The present research has the goal to equip an electrochemical microscopy laboratory able to study charge transfer (CT) reactions across interfaces of different kind. This goal has been reached acquiring the knowhow of the micro tips fabrication and setting up experimental systems for CT measurements at different type of interfaces. The Scanning ElectroChemical Microscopy (SECM) is used widely and the project involved the study of three kind of interfaces: a liquid/liquid ITIES, that is an Interface between Two Immiscible Electrolyte Solutions, a liquid/solid interface, formed by a glassy substrate covered by a thin film of silica with a Ruthenium(II) tris-bipyridile complex chemically linked to the lattice; and the last one was a liquid/swollen polymer interface

Molecular electron-transfer properties of Au-38 clusters

The electron transfer (ET) behavior of molecule-like Au38 clusters, protected by a phenyethanethiolate monolayer, Au38(SR)24, was studied on glassy carbon and platinum electrodes in N,N-dimethylformamide and dichloromethane. The kinetic parameters corresponding to the two first oxidation states (+1/0 and +2/+1) and the first reduction state (0/-1) were obtained by using cyclic voltammetric theory, convolution analysis, and global analysis. The ET properties of the anion electrogenerated from Au38(SR)24 were studied by homogeneous redox catalysis and using diphenyl disulfide as the acceptor, in comparison with ET results obtained by using conventional radical-anion donors. Both the heterogeneous and the homogeneous analyses point to a remarkably fast ET behavior typical of the formation and reactivity of delocalized ionic species in which solvent reorganization is the main factor controlling the intrinsic barrier

Active IrO2 and NiO thin films prepared by atomic layer deposition for oxygen evolution reaction

| openaire: EC/H2020/722614/EU//ELCORELAtomic layer deposition (ALD) is a special type of chemical vapor deposition (CVD) technique that can grow uniformed thin films on a substrate through alternate self-limiting surface reactions. Recently, the application of these thin film materials to catalytic systems has begun to attract much attention, and the capacity to deposit these catalytic films in a highly controlled manner continues to gain importance. In this study, IrO2 and NiO thin films (approximately 25 to 60 nm) were deposited on industrial Ni expanded mesh as an anode for alkaline water electrolysis. Different ALD operating parameters such as the total number of deposition cycles, sublimation and deposition temperatures, and precursors pulse and purge lengths were varied to determine their effects on the structure and the electrochemical performance of the thin film materials. Results from the electrochemical tests (6 M KOH, 80◦C, up to 10 kA/m2) showed the catalytic activity of the samples. Oxygen overpotential values (ηO2) were 20 to 60 mVlower than the bare Ni expanded mesh. In summary, the study has demonstrated the feasibility of using the ALD technique to deposit uniformed and electroactive thin films on industrial metallic substrates as anodes for alkaline water electrolysis.Peer reviewe

Benchmarking Perovskite Electrocatalysts’ OER Activity as Candidate Materials for Industrial Alkaline Water Electrolysis

The selection and evaluation of electrocatalysts as candidate materials for industrial alkaline water electrolysis is fundamental in the development of promising energy storage and sustainable fuels for future energy infrastructure. However, the oxygen evolution reaction (OER) activities of various electrocatalysts already reported in previous studies are not standardized. This work reports on the use of perovskite materials (LaFeO3, LaCoO3, LaNiO3, PrCoO3, Pr0.8Sr0.2CoO3, and Pr0.8Ba0.2CoO3) as OER electrocatalysts for alkaline water electrolysis. A facile co-precipitation technique with subsequent thermal annealing (at 700 °C in air) was performed. Industrial requirements and criteria (cost and ease of scaling up) were well-considered for the selection of the materials. The highest OER activity was observed in LaNiO3 among the La-based perovskites, and in Pr0.8Sr0.2CoO3 among the Pr-based perovskites. Moreover, the formation of double perovskites (Pr0.8Sr0.2CoO3 and Pr0.8Ba0.2CoO3) improved the OER activity of PrCoO3. This work highlights that the simple characterization and electrochemical tests performed are considered the initial step in evaluating candidate catalyst materials to be used for industrial alkaline water electrolysis