title: Reductant and sequence effects on the morphology and catalytic activity of peptide-capped Au nanoparticles.
abstract: The use of peptides as capping ligands for materials synthesis has been widely explored. The ambient conditions of bio-inspired syntheses using molecules such as peptides represent an attractive route for controlling the morphology and activity of nanomaterials. Although various reductants can be used in such syntheses, no comprehensive comparison of the same bio-based ligand with different reductants has been reported. In this contribution, peptides AuBP1, AuBP2, and Pd4 are used in the synthesis of Au nanoparticles. The reductant strength is varied by using three different reducing agents: NaBH4, hydrazine, and ascorbic acid. These changes in reductant produce significant morphological differences in the final particles. The weakest reductant, ascorbic acid, yields large, globular nanoparticles with rough surfaces, whereas the strongest reductant, NaBH4, yields small, spherical, smooth nanomaterials. Studies of 4-nitrophenol reduction using the Au nanoparticles as catalysts reveal a decrease in activation energy for the large, globular, rough materials relative to the small, spherical, smooth materials. These studies demonstrate that modifying the reductant is a simple way to control the activity of peptide-capped nanoparticles.
authors.affiliation: †Department of Chemistry, University of Miami, 1301 Memorial Drive, Coral Gables, Florida 33146, United States.
authors.forename: Beverly D
authors.initials: BD
authors.lastname: Briggs
authors.affiliation: ‡Department of Chemical and Biological Engineering, University at Buffalo (SUNY), Buffalo, New York 14260, United States.
authors.forename: Yue
authors.initials: Y
authors.lastname: Li
authors.affiliation: ‡Department of Chemical and Biological Engineering, University at Buffalo (SUNY), Buffalo, New York 14260, United States.
authors.forename: Mark T
authors.initials: MT
authors.lastname: Swihart
authors.affiliation: †Department of Chemistry, University of Miami, 1301 Memorial Drive, Coral Gables, Florida 33146, United States.
authors.forename: Marc R
authors.initials: MR
authors.lastname: Knecht
mesh_terms: D000595:Amino Acid Sequence; D002384:Catalysis / Q000187:drug effects; D006046:Gold / Q000737:chemistry*; D007700:Kinetics; D053768:Metal Nanoparticles / Q000737:chemistry* / Q000648:ultrastructure; D009596:Nitrophenols / Q000737:chemistry; D010084:Oxidation-Reduction / Q000187:drug effects; D010455:Peptides / Q000737:chemistry*; D019163:Reducing Agents / Q000494:pharmacology*; D013056:Spectrophotometry, Ultraviolet; D013816:Thermodynamics
chemical_list: D009596:Nitrophenols; D010455:Peptides; D019163:Reducing Agents; D006046:Gold; C024836:4-nitrophenol
keywords: Au nanoparticles; bio-inspired synthesis; catalysis; peptides; reductant