A (surface-enhanced) Raman spectroscopic study of the adsorption of S2O3.0.CO;2-4/asset/equation/tex2gif-stack-1.gif?v=1&t=h5kawjw4&s=16a98db97a533d73da733e50af96b898e4b6fb9a" class="inlineGraphic">− and SCN− on a silver deposit

✍ Scribed by D. Gonnissen; W. Langenaeker; A. Hubin; P. Geerlings

• Publisher: John Wiley and Sons
• Year: 1998
• Tongue: English
• Weight: 240 KB
• Volume: 29
• Category: Article
• ISSN: 0377-0486
• DOI: 10.1002/(sici)1097-4555(199812)29:12<1031::aid-jrs314>3.0.co;2-4

✦ Synopsis

The study of the adsorption behaviour of SCN-and at a silver substrate contributes substantially to an S 2 O 3 2improved insight into the electrochemical formation of a silver image in photographic development processes. (Surface-enhanced) Raman (SER) spectroscopy and quantum chemical calculations reveal the existence of an S coordination for both species with Ag, forming 1,1-AgSCN and surface complexes, respectively, at 1,1-AgS 2 O 3 the Ag electrode surface. At an electrode potential of Ô0.1 V vs. SCE, the SER peaks of adsorbed SCN-intensify when the bulk concentration is increased from 1 Â 10-4 to 6 Â 10-3 M, whereas those of adsorbed are S 2 O 3 2already measurable at a bulk concentration of 1 Â 10-5 M and saturate at 3 Â 10-4 M. In both cases, the AgÈS bond weakens when the potential is lowered from Ô0.1 to Ô0.5 V vs. SCE. The correspondence between SER and capacity measurements reveals that a decrease in potential also causes a decrease in the AgSCN surface concentration. The complex even disappears at potentials below Ô0.2 V vs. SCE. The formation of a physical 1,1-AgS 2 O 3 adsorption state at lower potentials is suggested.