Hidenori Noguchi

The potential dependence of the interfacial water structure at Pt and Au thin film electrodes was investigated by sum frequency generation (SFG) spectroscopy in internal reflection mode. In the case of the Pt electrode, two broad peaks were observed in the OH stretching region at ca. 3200 cm(-1) and ca. 3400 cm(-1), which are known to be due to the symmetric OH stretching (upsilon1) of tetrahedrally coordinated, i.e., strongly hydrogen bonded "ice-like" water, and the asymmetric OH stretching (u

The use of high-concentration electrolytes in lithium metal batteries enables the effective suppression of lithium dendrite growth at the lithium anode. The issue of the solvation structure at the electrolyte/electrode interface in low- and high-concentration electrolytes must be addressed to understand the electroreduction stability and solid–electrolyte interphase (SEI) formation. The concentration-dependent solvation structure of lithium bis(trifluoromethanesulfonyl)imide (LITFSI)–dimethyl su

Interfacial structures of water at polyvinyl alcohol (PVA) and poly(2-acrylamido-2-methypropane) sulfonic acid sodium salt (PNaAMPS)/quartz interfaces were investigated by sum frequency generation (SFG) spectroscopy. Two broad peaks were observed in OH stretching region at 3200 and 3400 cm(-1), corresponding to the symmetric OH stretching of tetrahedrally coordinated, i.e., strongly hydrogen bonded "ice-like" water, and the asymmetric OH stretching of water in a more random arrangement, i.e., we

Humidity-dependent water structure on the Nafion thin film surface was determined at room temperature by using sum frequency generation spectroscopy (SFG). When the Nafion thin film was exposed to a low relative humidity (RH) environment, a peak at 3720 cm−1 due to the “dangling OH” or “free OH” of water molecules and a peak centered around 3600 cm−1, which was assigned to be due to water molecules interacting with sulfonate groups of the Nafion surface, were observed. The intensities of these p

Increasing demands for the development of efficient electrochemical energy systems such as fuel cells and metal–air batteries have stimulated research interests in investigating the mechanistic pathway of the oxygen reduction reaction (ORR) at the catalyst surface, having direct relevance to these systems. Although past years have witnessed few efforts toward illustrating the mechanistic pathway of the ORR under various pH conditions, the chemical nature of intermediates generated under the acid

The surface dynamics of adsorbed CO molecules formed by dissociative adsorption of HCHO at a polycrystalline Pt electrode/electrolyte solution interface was studied by picosecond time-resolved sum-frequency generation (TR-SFG) spectroscopy. A SFG peak at 2050-2060 cm(-1) was observed at the Pt electrode in HClO(4) solution containing HCHO at 0-300 mV (vs Ag/AgCl), indicating the formation of adsorbed CO at an atop site of the Pt surface as a result of dissociative adsorption of HCHO. The peak po

Abstract The molecular orientation in self-assembled monolayer (SAM) of octadecanethiol (ODT) on platinum surface prepared in ethanol solution was examined by broad-bandwidth sum frequency generation (BB-SFG) spectroscopy. The bands attributed to the CH3 symmetric and asymmetric stretching vibrational modes were observed in the SFG spectra. From the analysis of SFG intensity ratio of these two modes, the alkyl chain on platinum was found to be more perpendicular to the substrate than those on go