Electrolytic Synthesis of Aqueous Aluminum Nanoclusters and in situ Characterization by Femtosecond Raman Spectroscopy and Computations

 

   

Electrolytic Synthesis of Aqueous Aluminum Nanoclusters and in situ Characterization by Femtosecond Raman Spectroscopy and Computations

Abstract : The selective synthesis and in situ characterization of aqueous Al-containing clusters is a long-standing challenge. We report a new integrated platform that combines: (i) a selective, atom-economical, step-economical, scalable synthesis of Al-containing nanoclusters in water via precision electrolysis with strict pH control; and (ii) an improved femtosecond stimulated Raman spectroscopic method covering a broad spectral range of ca. 350—1400 cm-1 with high sensitivity, aided by ab initio computations, to elucidate Al aqueous cluster structures and formation mechanisms in real time. Using this platform, a new and unique view of flat [Al133-OH)62-OH)18(H2O)24](NO3)15 cluster formation is observed in water, in which three distinct reaction stages are identified. The initial stage involves the formation of an [Al73-OH)62-OH)6(H2O)12]9+ cluster core as an important intermediate toward the flat Al13 aqueous cluster.

Wang, W.; Liu, W.; Chang, I.-Y.; Wills, L. A.; Zakharov , L. N.; Boettcher , S. W.; Cheong, P. H.-Y.;  Fang, C.; Keszler, D. A. Proc. Natl. Acad. Sci. USA 2013, Accepted. DOI: 10.1073/pnas.1315396110