12For the first time a series of anionic surfactant ionic liquids (SAILs) have been synthesized based on 13 organic surfactant anions and 1-butyl-3-methyl-imidazolium cations. These compounds are more 14 environmentally friendly and chemically tuneable as compared to other common ionic liquids. A detailed 15 investigation of physico-chemical properties highlights potential applications from battery design to reaction 16 control, and studies into aqueous aggregation behaviour, as well as structuring in pure ILs, point to possible 17 uses in electrochemistry.

Nanostructuring boron-doped diamond (BDD) films increases their sensitivity and performance when used as electrodes in electrochemical environments. We have developed a method to produce such nanostructured, porous electrodes by depositing BDD thin film onto a densely packed "forest" of vertically aligned multiwalled carbon nanotubes (CNTs). The CNTs had previously been exposed to a suspension of nanodiamond in methanol causing them to clump together into "teepee" or "honeycomb" structures. These nanostructured CNT/BDD composite electrodes have been extensively characterized by scanning electron microscopy, Raman spectroscopy, cyclic voltammetry, and electrochemical impedance spectroscopy. Not only do these electrodes possess the excellent, well-known characteristics associated with BDD (large potential window, chemical inertness, low background levels), but also they have electroactive areas and double-layer capacitance values ∼450 times greater than those for the equivalent flat BDD electrodes.

The oxidations of carbon monoxide and formic acid at ultrathin Pd layers grown on Au nanoparticles were studied as a function of Pd thickness. Pd shells with thickness between 1 and 10 nm were grown on 19 nm Au nanoparticles by chemical reduction of H 2 PdCl 4 with ascorbic acid. High-resolution transmission electron microscopy and X-ray diffraction confirm the coreÀshell configuration of the nanostructures. While the synthesis of pure Pd nanostructures led to a rather amorphous material, Pd nanoshells exhibited a polycrystalline structure confirming that Au nanostructures act as templates for Pd growth. Three-dimensional assemblies of nanoparticles were generated by alternate electrostatic layer-by-layer adsorption steps, involving poly-L-lysine and colloidal dispersions. Electrochemical studies in H 2 SO 4 containing electrolyte solution demonstrate that CO coverage and anodic stripping potential are affected by the thickness of Pd nanoshells. In addition, the faradaic current density associated with HCOOH oxidation significantly increases with increasing Pd thickness. The thickness-dependent reactivity of Pd nanoshells is discussed in terms of lattice strain relaxation.

The mechanism of CO and HCOOH electrooxidation in an acidic solution on carbon-supported Au–Pd core–shell nanoparticles was investigated by differential electrochemical mass spectrometry and in situ Fourier transform infrared (FTIR) spectroscopy. Analysis performed in nanostructures with 1.3 ± 0.1 nm (CS1) and 9.9 ± 1.1 nm (CS10) Pd shells provides compelling evidence that the mechanism of adsorbed CO (COads) oxidation is affected by structural and electronic effects introduced by the Au cores. In the case of CS10, a band associated with adsorbed OH species (OHads) is observed in the potential range of CO oxidation. This feature is not detected in the case of CS1, suggesting that the reaction follows an alternative mechanism involving COOHads species. The faradaic charge associated with COads oxidation as well as the Stark slope measured from FTIR indicates that the overall affinity and orbital coupling of CO to Pd are weaker for CS1 shells. FTIR spectroscopy also revealed the presence of HCOOads intermediate species only in the case of CS1. This observation allowed us to conclude that the higher activity of CS10 toward this reaction is due to a fast HCOOads oxidation step, probably involving OHads, to generate CO2. Density functional theory calculations are used to estimate the contributions of the so-called ligand and strain effects on the local density of states of the Pd d-band. The calculations strongly suggest that the key parameter contributing to the change in mechanism is the effective lattice strain.

No abstract