US EPA

5365256 

Journal Article 

Improved surface properties and catalytic activity of anisotropic shapes of photoetched Au nanostructures formed by variable energy laser exposure 

Kaur, R; Pal, B 

2014 

Yes 

Journal of Molecular Catalysis A: Chemical
ISSN: 1381-1169 

ELSEVIER 

AMSTERDAM 

395 

7-15 

English 

10.1016/j.molcata.2014.07.025 

WOS:000347498500002 

Anisotropic Au nanostructures with versatile shapes have been prepared in a single step through cost effective laser irradiation approach with different laser energies (≈2.41, 2.50 and 2.71 eV) and investigated the changes in optoelectronic and catalytic properties. A variety of irregular Au nano-morphologies such as spheres (5-20 nm), low aspect ratio rods, nano-capsules, oval egg shaped particles, ice cubes (∼7 nm), truncated triangles (∼7-8 nm), pentagonal (∼12 nm), square shaped particles (∼8 nm) and polygonal nanospheres (∼8-12 nm) were formed after laser exposure. The modified surface morphology of photoetched Au nanoparticles was monitored by variable energy laser beam, follows an exponential (A = A 0 e-kt) disintegration rate as a function of particle geometric size and shape. The percentage decomposition of Au nanorods (aspect ratio = 2.8) is found to increase as 59% > 69% > 72% with increased laser energy exposure; 2.41 eV (514.7 nm) > 2.50 eV (488 nm) > 2.71 eV (457.9 nm) as determined from the decrease in surface plasmon absorption band during laser illumination. The formation of small clusters on laser irradiation has resulted in the decrease of zeta potential from +49.79 (unetched particles) to +12.71 mV (etched particles) and also conductance values. Catalytic reduction of p-nitrophenol to p-aminophenol and m-dinitrobenzene to m-phenylenediamine with photofragmented Au nanostructures is found to be ∼15-20% higher than non-etched Au particles. © 2014 Elsevier B.V. All rights reserved. 

Photoetched Au particles; Anisotropic Au morphology; Laser photofragmentation; Zeta potential; Catalytic reduction