Au Nanorods and Pd Nanoparticles Department of Chemical and Biomolecular Engineering Rice University, Houston, TX Sriram Chandrasekhar Prof. Michael S. Wong

Experiments Summary

Au Nanorods Synthesis Method: Nikoobakht & El-Sayed. Chem. Mater., Vol. 15, No. 10, 2003 Seed Solution CTAB: 5.0 ml, 0.20M HAuCl 4 : 5.0 ml, M NaBH 4 : 0.6 ml, 0.01M (iced) Rigorous Stirring Growth Solution CTAB: 5.0 ml, 0.20M AgNO 3 : [ ] ml, 0.004M HAuCl 4 : 5.0 ml, 0.001M Ascorbic Acid: 70ul, M Product Seed Solution: 12 ul Add to Growth Solution Wait min 0.05ml AgNO ml AgNO ml AgNO ml AgNO ml AgNO 3 Seed SolutionGrowth Solution Products after 20 mins

Product Pictures 0.05ml AgNO ml AgNO ml AgNO ml AgNO ml AgNO 3 Products after 20 mins Products after 10 mins 0.05ml AgNO ml AgNO ml AgNO ml AgNO ml AgNO 3

Au Nanorods Characterization UV-Vis Spectra of synthesized Au NRsUV-Vis Spectra of Au NRs from Paper The two spectra compare favorably with peaks at similar wavelengths indicating a successful synthesis of Au NRs of different lengths. The sample with 0.15 ml of AgNO 3 did not grow to the expected length, but this is likely due to human error in preparation.

Pd Nanocubes Synthesis Na 2 PdCl 4 + KBr In 3ml DEG PVP + 8ml DEG 11 mL DEG 15.0 mM Na 2 PdCl mM KBr 67 mM PVP Parr: oven 100 ºC, 3h Product Expected length: 12nm (Dark Brown) Method: Xia et al; J. Am. Chem. Soc., Vol 129, No. 12, 2007 DEG = diethylene glycol

Pd Icosahedra Synthesis Na 2 PdCl 4 In water Citric Acid + PVP In water 11 mL solution 5.8 mM Na 2 PdCl 4 28 mM Citric Acid 29 mM PVP Parr: oven 90 ºC, 26h Product Expected edge lengths: 25nm (Grey) Method: Xia et al; Adv. Funct. Mater. Vol 19, pg , 2009 DEG = diethylene glycol

Motivation for DEG NCube Synthesis  Pd Cuboctahedra thermodynamically favorable shape; 4nm edge length  Gives the highest catalytic activity among Pd-only NPs.  Cuboctahedra have 6 {100} and 8 {111} facets  Paper determines that slow reduction of Pd salt leads to Ncubes; DEG is a weak reducing agent  Result of DEG reduction in paper: NCubes with edge length: 8nm Facets: All {100} facets

TCE HDC Reaction The Pd nanocubes showed better catalytic activity Rate constants were calculated using the formula: kt = ln(1/(1-X)) where X is conversion. Thus k is the slope from a plot of ln(1/(1-X)) vs. t Normalized Mass Ethane/Pentane IcosahedraNanocube k

Core/Shell Nbars  Au NR Synthesis: same procedure as described above  Required chemicals are available