Atomically precise silver clusters for efficient chlorocarbon degradation

We describe the degradation of chlorocarbons (CCl sub(4), C sub(6)H sub(5)CH sub(2)Cl and CHCl sub(3)) in solution at room temperature (27 plus or minus 4 degree C) by the monolayer-protected silver quantum cluster, Ag sub(9)MSA sub(7) (MSA: mercaptosuccinic acid) in the presence of isopropyl alcohol (IPA). The main degradation products were silver chloride and amorphous carbon. Benzyl chloride was less reactive towards clusters than CCl sub(4) and CHCl sub(3). Materials used in the reactions and the reaction products were characterized using several spectroscopic and microscopic tools such as ultraviolet-visible (UV/Vis) absorption spectroscopy, Fourier transform infrared spectroscopy (FTIR), photoluminescence spectroscopy, X-ray diffraction (XRD), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), energy dispersive analysis of X-rays (EDAX) and scanning electron microscopy (SEM). We have shown that clusters are more efficient for the degradation of halocarbons than the corresponding monolayer-protected nanoparticles (Ag[at]MSA, particle diameter 15 plus or minus 5 nm) at a given time and temperature. The higher reactivity of clusters is attributed to their small size and large surface area. Clusters and nanoparticles were used for reactions in supported (on neutral alumina) and unsupported forms. A possible mechanism for the reaction has been postulated on the basis of experimental results.