Chemisorption of Phosphine on Colloidal Silver in Aqueous Solution

Abstract

The plasmon absorption band of 6-nm silver particles in aqueous solution is blue-shift4 and strongly broadened upon the adsorption of phosphine, PH3. The effects are more pronounced in alkaline than acidic solution. In alkaline solution, the adsorption is completely irreversible. Upon aging of the silver solutions containing PH3, hydrogen and phosphate are generated in the mole ratio 4: 1. A mechanism is proposed for the catalytic action of the silver particles in the reaction of phosphine with water, in which donation of electron density from absorbed phosphine into the silver particles is an important step. Conductivity measurements indicate that phosphine in alkaline solution is adsorbed as PH2-. It is shown in coadsorption experiments that phosphine is more strongly adsorbed than I-and that SH-and phosphine are about equally strongly adsorbed.

Tuning the electronic structure of solids with nanometer-sized microstructures

“…6) which comes close to the one suggested in section 3.1 are electrochemical cells used for studying the modulation of the electroreflectance of Au or other metals (6). The change in the optical reflectivity of metals (Fig.…”

“…The absorption band is damped and blue shifted. This blue shift is known to result from the injection of electrons from the phosphine molecules into the conduction band of Ag [6]. Similar interactions of various nucleophilic reagents with nanometer-sized crystallites of Ag, Pd and Ag-Hgalloys have been reported in the past [7][8][9].…”

“…Fig. 3 displays the variation of the plasmon absorption band of 5 nm Ag crystals in aqueous solution due to the chemisorption of various densities of phosphine molecules at the free surface of the Ag crystals [6]. The absorption band is damped and blue shifted.…”

“…3. Absorption band of nanometer-sized silver crystals before and after the addition of various amounts of phosphine [6]. .…”

Spectroelectrochemical studies of plasmon coupled silver nanoparticles

“…Potential-induced spectral changes in nanoparticles have been the topic of several early studies. The frequency of the metal phase can also be changed by the addition of redox couples to the suspension or generation of redox active radicals by ionizing radiation [5,6]. Mulvaney et al [4] observed spectral changes of the plasmon resonance of small (ca.…”