The properties of confined liquid water, or liquid water in contact with hydrophobic surfaces, are significantly different from those of bulk liquid water. However, all of water's commonly described properties are related to inert "bulk liquid water" which comprises a tetrahedral hydrogen-bonded network. In this work, we report an innovative and facile method for preparing small water clusters (SWCs) with reduced affinity hydrogen bonds by letting bulk water flow through supported Au nanoparticles (NPs) under resonant illumination to give NP-treated (AuNT) water at constant temperature. Utilizing localized surface plasmon resonance on illuminated Au NPs, the strong hydrogen bonds of bulk water can be disordered when water is located at the illuminated Au/water interface. The prepared SWCs are free of Au NPs. The energy efficiency for creating SWCs is ∼17%. The resulting stable AuNT water exhibits distinct properties at room temperature, which are significantly different from the properties of untreated bulk water, examples being their ability to scavenge free hydroxyl and 2,2-diphenyl-1-picrylhydrazyl radicals and to effectively reduce NO release from lipopolysaccharide-induced inflammatory cells.

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In this work, different conditions for electrochemically roughening silver substrates were investigated to obtain the best surface-enhanced Raman scattering (SERS) performance. Experimental results indicate that Ag electrodes can be cycled in deoxygenated aqueous solutions containing 0.1 N HCl from À0.3 to +0.2 V vs. Ag/AgCl at 25 mV s À1 for five scans to obtain the strongest SERS effects. Using this substrate, the SERS intensity of adsorbed Rhodamine 6G (R6G) can be increased 9-fold, compared with that of R6G adsorbed on an Ag substrate prepared using the general literature methods. Moreover, the SERS enhancement capabilities of the newly developed Ag substrate seriously decays at 200 C, compared to 125 C for the generally roughened Ag substrates. The reduction of the SERS intensity upon aging is also lessened for this newly developed substrate. Further investigations revealed that surface morphology and the Cl content on the roughened Ag substrates have significant influence on the corresponding SERS performances.

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We develop an easy and effective pathway to improve surface-enhanced Raman scattering (SERS) effects of probe molecules of Rhodamine 6G (R6G) adsorbed on electrochemically prepared roughened Ag substrates. In general SERS studies, SERS-active metal substrates are first prepared. Then probe molecules are adsorbed on them to evaluate the relative SERS effects. In this study, we employ electrochemical oxidation-reduction cycle (ORC) treatments in 0.1 M KCl solutions containing probe molecules of 2 x 10(-5) M R6G to prepare R6G-adsorbed SERS-active Ag substrates for one step. Encouragingly, based on this strategy, the SERS intensity of adsorbed R6G can be increased by 1 order of magnitude, as compared with that of R6G adsorbed on a roughened Ag substrate beforehand, which was generally shown in the literature. Moreover, this improved SERS effect based on this strategy is also effective for 2 x 10(-9) M probe molecules, which is at a level of single molecule detection based on Ag colloids. It is also effective for probe molecules of ClO(4)(-) with low Raman cross section and for other electrochemically prepared SERS-active substrates of Au. Further analyses indicate that the increase in SERS activity in this new method is most likely due to the incorporation of more chloride ions into the substrate.