Raman spectroscopy

About: Raman spectroscopy is a research topic. Over the lifetime, 122605 publications have been published within this topic receiving 2891083 citations. The topic is also known as: Raman Spectrum Analysis & spectrum Analysis, Raman.

Raman shifts in Si nanocrystals

Abstract: Raman shifts of Si nanocrystals versus size were studied theoretically by a bond polarizability model. Zero‐dimensional spheres and one‐dimensional columns were considered. The relation between the Raman shift and the size for Si spheres and columns was established, from which the size of Si nanocrystals can be obtained for a given Raman shift or vice versa.

In situ Raman spectroscopic evidence for oxygen reduction reaction intermediates at platinum single-crystal surfaces

Abstract: Developing an understanding of structure–activity relationships and reaction mechanisms of catalytic processes is critical to the successful design of highly efficient catalysts. As a fundamental reaction in fuel cells, elucidation of the oxygen reduction reaction (ORR) mechanism at Pt(hkl) surfaces has remained a significant challenge for researchers. Here, we employ in situ electrochemical surface-enhanced Raman spectroscopy (SERS) and density functional theory (DFT) calculation techniques to examine the ORR process at Pt(hkl) surfaces. Direct spectroscopic evidence for ORR intermediates indicates that, under acidic conditions, the pathway of ORR at Pt(111) occurs through the formation of HO2*, whereas at Pt(110) and Pt(100) it occurs via the generation of OH*. However, we propose that the pathway of the ORR under alkaline conditions at Pt(hkl) surfaces mainly occurs through the formation of O2−. Notably, these results demonstrate that the SERS technique offers an effective and reliable way for real-time investigation of catalytic processes at atomically flat surfaces not normally amenable to study with Raman spectroscopy. The oxygen reduction reaction, catalysed by platinum, is a crucial process in the operation of fuel cells, but the mechanistic pathways through which it occurs remain a matter for debate. Here, the authors use in situ Raman spectroscopy to identify key intermediates for this reaction at different atomically flat platinum surfaces, shedding light on the mechanism.

Functionalization of single-walled carbon nanotubes with well-defined polystyrene by "click" coupling.

Abstract: Covalent functionalization of alkyne-decorated SWNTs with well-defined, azide-terminated polystyrene polymers was accomplished by the Cu(I)-catalyzed [3 + 2] Huisgen cycloaddition. This reaction was found to be extremely efficient in producing organosoluble polymer-nanotube conjugates, even at relatively low reaction temperatures (60 °C) and short reaction times (24 h). The reaction was found to be most effective when a CuI catalyst was employed in the presence of 1,8-diazabicyclo[5.4.0]undec-7-ene as an additive. IR spectroscopy was utilized to follow the introduction and consumption of alkyne groups on the SWNTs, and Raman spectroscopy evidenced the conversion of a high proportion of sp2 carbons to sp3 hybridization during alkyne introduction. Thermogravimetric analysis indicated that the polymer-functionalized SWNTs consisted of 45% polymer, amounting to approximately one polymer chain for every 200−700 carbons of the nanotubes, depending on polymer molecular weight. Transmission electron microscopy an...