Optimizing detection sensitivity on surface-enhanced Raman scattering of transition-metal electrodes with confocal Raman microscopy.

Some points on how to improve the detection sensitivity of confocal Raman microscopy for the study of surface-enhanced Raman scattering (SERS) of transition-metal electrodes are discussed, including the careful design of the spectroelectrochemical cell, proper selection of the thickness of the solution layer, the binning of charge-coupled device (CCD) pixels, and appropriate setting of the notch filter. Various roughening methods for the Pt, Rh, Fe, Co, and Ni electrode surfaces have been introduced in order to obtain SERS-active surfaces. It has been shown that the appropriate roughening procedure and the optimizing performance of the confocal Raman microscope are the two most important factors to directly generate and observe SERS on net transition-metal electrodes.

PVP-coated iron nanocrystals: Anhydrous synthesis, characterization, and electrocatalysis for two species.

We report the synthesis of Fe nanocrystals (approximately 9 nm) in an anhydrous media, formamide, using poly(N-vinyl-2-pyrrolidone) (PVP) as a protecting agent. The morphology, structure, and composition of the PVP-coated Fe nanocrystals are studied by transmission electron microscopy (TEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and FT-Raman spectroscopy. The surface properties of the PVP-coated Fe nanocrystals are studied by electrochemistry and micro-surface-enhanced Raman scattering (mSERS) using pyridine as a probing molecule. The PVP-coated Fe nanocrystals, when immobilized on an electrode substrate, display very good electrocatalytic activities in the selective reduction of H2O2 in the presence of oxygen and in the oxidation of NO.