Adsorption configuration of sodium 2-quinoxalinecarboxylate on iron substrate: Investigation by in situ SERS, XPS and theoretical calculation.

The adsorption geometry of sodium 2-quinoxalinecarboxylate (2-QC) on iron surface was investigated by in situ surface-enhanced Raman scattering spectroscopy (SERS) and X-ray photoelectron spectroscopy (XPS) measurements. The density functional theory (DFT) calculations predicted that 2-QC ion was a highly efficient inhibitor and N as well as O atoms were the possible adsorption centers, and theoretically offered the Raman-active band position and intensity. Potential-dependent SERS results suggested that the 2-QC strongly bonded to the iron surface via the lone pair electrons of the two O atoms of the carboxylate group in a bidentate configuration with a vertical orientation at more positive potentials; However, at -1.

Exploring electrosorption at iron electrode with in situ surface-enhanced infrared absorption spectroscopy.

Surface-enhanced infrared absorption spectroscopy (SEIRAS) in attenuated total reflection (ATR) configuration has been extended to the Fe electrode/electrolyte interface in neutral and weakly acidic solutions for the first time. The SEIRA-active Fe film electrode was obtained through a potentiostatic electrodeposition of a virtually pinhole-free 40 nm-thick Fe overfilm onto a 60 nm-thick Au underfilm chemically predeposited on the reflecting plane of an ATR Si prism. The infrared absorption for CO adlayer at the Fe film electrode measured with ATR-SEIRAS was enhanced by a factor of larger than 34, as compared to that at a Fe bulk electrode with external infrared absorption spectroscopy in the literature.

Attenuated total reflection surface-enhanced infrared absorption spectroscopy at a cobalt electrode.

In situ surface-enhanced infrared absorption spectroscopy (SEIRAS) in attenuated total reflection (ATR) configuration has been extended to a Co electrode fabricated by potentiostatic deposition of a 50-nm-thick Co overlayer onto a Au underlayer chemically preformed on the reflecting plane of an ATR Si hemi-cylindrical prism. The as-prepared Co-on-Au film was characterized with atomic force microscopy (AFM) and X-ray photoelectron spectroscopy (XPS). The AFM images of the films before and after Co coating revealed island structures facilitating the SEIRA effect with Co nanoparticles much smaller than the underlying Au ones.

Seeded-growth approach to fabrication of silver nanoparticle films on silicon for electrochemical ATR surface-enhanced IR absorption spectroscopy.

Ag nanoparticle films (simplified as nanofilms hereafter) on Si for electrochemical ATR surface enhanced IR absorption spectroscopy (ATR-SEIRAS) have been successfully fabricated by using chemical deposition, which incorporates initial embedding of Ag seeds on the reflecting plane of an ATR Si prism and subsequent chemical plating of conductive and SEIRA-active Ag nanofilms. Two alternative methods for embedding initial Ag seeds have been developed: one is based on self-assembly of Ag colloids on an aminosilanized Si surface, whereas the other the reduction of Ag+ in a HF-containing solution. A modified silver-mirror reaction was employed for further growth of Ag seeds into Ag nanofilm electrodes with a theoretically average thickness of 40-50 nm.

In situ surface-enhanced IR absorption spectroscopy on CO adducts of iron protoporphyrin IX self-assembled on a Au electrode.

The surface coordination chemistry of carbon monoxide with the reduced form (Fe(II)PP) of iron(III) protoporphyrin IX (Fe(III)PP) monolayer self-assembled on a Au electrode in 0.1 M HClO4 was studied for the first time by using in situ ATR-surface-enhanced infrared absorption spectroscopy (ATR-SEIRAS). Both mono- and biscarbonyl adducts [simplified as Fe(II)(CO)PP and Fe(II)(CO)2PP, respectively] were detected, depending on the history of potential control.

Tunable surface-enhanced infrared absorption on au nanofilms on si fabricated by self-assembly and growth of colloidal particles.

Au colloids were used to fabricate nanoscale-tunable Au nanofilms on silicon for surface-enhanced IR absorption bases in both ambient and electrochemical environments. This wet process incorporates the self-assembly of colloidal Au monolayer using 3-aminopropyl trimethoxysilane as the organic coupler with subsequent chemical plating in an Au(III)/hydroxylamine solution. FTIR spectroscopy in transmission mode of the probe species SCN- was used to evaluate the apparent surface enhancement in IR absorption of 2D Au colloid arrays and chemically plated Au particles.

Ubiquitous strategy for probing ATR surface-enhanced infrared absorption at platinum group metal-electrolyte interfaces.

A versatile two-step wet process to fabricate Pt, Pd, Rh, and Ru nanoparticle films (simplified as nanofilms hereafter) for in situ attenuated total reflection Fourier transform infrared (ATR-FTIR) study of electrochemical interfaces is presented, which incorporates an initial chemical deposition of a gold nanofilm on the basal plane of a silicon prism with the subsequent electrodepostion of desired platinum group metal overlayers. Galvanostatic electrodeposition of Pt, Rh, and Pd from phosphate or perchloric acid electrolytes, or potentiostatic electrodeposition of Ru from a sulfuric acid electrolyte, yields sufficiently "pinhole-free" overlayers as evidenced by electrochemical and spectroscopic characterizations. The Pt group metal nanofilms thus obtained exhibit strongly enhanced IR absorption.

Extending in situ attenuated-total-reflection surface-enhanced infrared absorption spectroscopy to ni electrodes.

Surface-enhanced infrared absorption spectroscopy (SEIRAS) in the attenuated-total-reflection configuration (ATR-SEIRAS) has been applied for the first time to Ni electrodes. SEIRA-active Ni electrodes were obtained through initial chemical deposition of a 60-nm-thick Au underlayer on the reflecting plane of an ATR Si prism followed by potentiostatic electrodeposition of a 40-nm-thick Ni overlayer in a modified Watt's electrolyte. The Ni nanoparticle film thus obtained exhibited exceptionally enhanced IR absorption for the surface probe molecule CO while maintaining unipolar and normally directed bands.