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Formation of Bimetallic Copper–Gold Alloy Nanoparticles Probed by in Situ X‐ray Absorption Fine Structure Spectroscopy
Author(s) -
Destro Priscila,
Cantaneo Daniel Augusto,
Meira Débora M.,
dos Santos Honório Guilherme,
da Costa Luelc Souza,
Bueno José Maria C.,
Zanchet Daniela
Publication year - 2018
Publication title -
european journal of inorganic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.667
H-Index - 136
eISSN - 1099-0682
pISSN - 1434-1948
DOI - 10.1002/ejic.201800413
Subject(s) - x ray absorption fine structure , nanoparticle , alloy , bimetallic strip , chemistry , copper , absorption spectroscopy , absorption (acoustics) , x ray absorption spectroscopy , phase (matter) , amorphous solid , spectroscopy , chemical engineering , colloid , colloidal gold , extended x ray absorption fine structure , metal , nanotechnology , crystallography , materials science , composite material , organic chemistry , optics , physics , quantum mechanics , engineering
Advanced studies of the formation and growth processes of metal alloy nanoparticles are of great importance and provide a better understanding for the fine tuning of their properties for the desired applications. In this work, we followed the synthesis of Au 1– x Cu x colloidal nanoparticles by in situ time‐resolved X‐ray absorption fine structure (XAFS) spectroscopy. The particles were synthesized by a one‐pot approach with a homemade reactor adapted to the XAFS measurements. The colloidal nanoparticles were also characterized by complementary ex situ techniques. Analyses at the Cu‐ K edge and Au‐ L 3 edge confirmed that the initial reduction of the Au species occurs at low temperatures (<100 °C) to form Au seeds that are subsequently enriched with Cu to form Au 0.75 Cu 0.25 alloy nanoparticles at 225 °C. An important finding was the temporary formation of a Cu 2 O‐type phase during the colloidal synthesis. This phase was consumed with the concomitant formation of the Au 1– x Cu x alloy nanoparticles. These results directly confirm the previous proposal that the alloy formation occurs through a digestive‐ripening‐like process of an amorphous Cu‐enriched phase.