TY - JOUR
T1 - Gold nanoparticles in novel green deep eutectic solvents
T2 - self-limited growth, self-assembly & catalytic implications
AU - O'Neill, Maeve
AU - Raghuwanshi, Vikram Singh
AU - Wendt, Robert
AU - Wollgarten, Markus
AU - Hoell, Armin
AU - Rademann, Klaus
PY - 2015/2/28
Y1 - 2015/2/28
N2 - In this article, we are reporting the catalytic activity of gold nanoparticles (AuNPs) dispersed in a novel eco-friendly Deep Eutectic Solvent (DES; choline chloride and urea) at room temperature. A low energy sputter deposition method is employed to synthesize AuNPs on the DES surface. This is a simple, economical and clean method for producing monodisperse gold nanoparticles by a self-limited growth mechanism. Detailed Small Angle X-ray Scattering (SAXS), UV-Vis and Transmission Electron Microscopy (TEM) investigations show the formation of spherical AuNPs of 5 nm in diameter. Moreover, these particles have a strong tendency to self-assemble at the DES surface as well as into the bulk. This is a new addition to a novel generation of gold based catalysts. The catalytic activity of Au nanoparticles in DES is revealed quantitatively by analyzing the apparent conversion reaction rate constant Kapp of para-nitrophenol to paraaminophenol in the presence of sodium borohydride. Catalytic activity reported in the present article ismuch faster (kapp = 0.34 s-1) than the rate reported earlier (kapp = 0.030 min-1) by Chirea et al. for gold nanowire networks [Langmuir, 2011, 27, 3906]. In agreement with the literature, we explain the higher catalytic activity in terms of a larger surface area of AuNPs in a non-self-assembled state.
AB - In this article, we are reporting the catalytic activity of gold nanoparticles (AuNPs) dispersed in a novel eco-friendly Deep Eutectic Solvent (DES; choline chloride and urea) at room temperature. A low energy sputter deposition method is employed to synthesize AuNPs on the DES surface. This is a simple, economical and clean method for producing monodisperse gold nanoparticles by a self-limited growth mechanism. Detailed Small Angle X-ray Scattering (SAXS), UV-Vis and Transmission Electron Microscopy (TEM) investigations show the formation of spherical AuNPs of 5 nm in diameter. Moreover, these particles have a strong tendency to self-assemble at the DES surface as well as into the bulk. This is a new addition to a novel generation of gold based catalysts. The catalytic activity of Au nanoparticles in DES is revealed quantitatively by analyzing the apparent conversion reaction rate constant Kapp of para-nitrophenol to paraaminophenol in the presence of sodium borohydride. Catalytic activity reported in the present article ismuch faster (kapp = 0.34 s-1) than the rate reported earlier (kapp = 0.030 min-1) by Chirea et al. for gold nanowire networks [Langmuir, 2011, 27, 3906]. In agreement with the literature, we explain the higher catalytic activity in terms of a larger surface area of AuNPs in a non-self-assembled state.
KW - Catalysis
KW - Gold
KW - Nanoparticles
KW - Para-Nitrophenol Reduction
KW - Reaction Kinetics
KW - Self-Assembly
KW - Self-Limited Growth
UR - http://www.scopus.com/inward/record.url?scp=84920409199&partnerID=8YFLogxK
U2 - 10.1515/zpch-2014-0644
DO - 10.1515/zpch-2014-0644
M3 - Article
AN - SCOPUS:84920409199
VL - 229
SP - 221
EP - 234
JO - Zeitschrift fur Physikalische Chemie
JF - Zeitschrift fur Physikalische Chemie
SN - 0942-9352
IS - 1-2
ER -