| Hematite nanoparticles have been functionalized with a self-assembled monolayer of undecanoic acid (UA) by covalent attachment via siloxane groups. The number density of carboxylic/carboxylate groups on the surface was determined by titration and consistent with a closed-packed monolayer. The ability of these functionalized particles to adsorb Cd2+ in the ppm range was demonstrated using in situ anodic stripping voltammetry.;A probe beam deflection method that allows for the heat generated or absorbed during an interfacial process to be determined in situ is herein described. These optical measurements are performed using a collimated laser beam propagating parallel to the interface through the back of a flat, optically transparent ZnSe crystal that supports a very thin film of a metal electrode in contact with the electrolyte solution. Analysis of experimental data collected for a Au electrode in sulfuric acid aqueous solutions using numerical simulations were found to be consistent with the release of ∼375 kJ/mol upon formation of a monolayer of Au oxide.;The transient response of a series RC equivalent circuit to a staircase (SC) potential perturbation has been examined theoretically using experimental data reported for the Pt(111)|0.1 M HClO4 interface as a model system. Solutions to the governing algebraic differential equation were obtained by numerical techniques. In general, the resulting curves were not only found to be sensitive to the time at which the current was sampled within each step, but, also, quite different than those obtained by scanning the potential at a constant rate, as in conventional linear scan voltammetry (LSV). Better agreement between the SC and LSV results could be achieved based on values of the average step currents, Qstep/T. |
