A dispenser-reactor apparatus applied for in situ XAS monitoring of Pt nanoparticle formation.
In situ time-resolved X-ray absorption spectroscopy (XAS) measurements collected at the Pt L3-edge during the synthesis of Pt nanoparticles (NPs) in aqueous solution are reported. A specially designed dispenser-reactor apparatus allowed for monitoring changes in the XAS spectra from the earliest moments of Pt ions in solution until the formation of metallic nanoparticles with a mean diameter of 4.9 ± 1.1 nm. By monitoring the changes in the local chemical environment of the Pt atoms in real time, it was possible to observe that the NPs formation kinetics involved two stages: a reduction-nucleation burst followed by a slow growth and stabilization of NPs. Subsequently, the synthesized Pt NPs were supported on activated carbon and characterized by synchrotron-radiation-excited X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD) and extended X-ray absorption fine structure (EXAFS). The supported Pt NPs remained in the metallic chemical state and with a reduced size, presenting slight lattice parameter contraction in comparison with the bulk Pt values.
Laboratório de Espectroscopia de Elétrons (LEe-), Instituto de Física, Universidade Federal do Rio Grande do Sul (UFRGS), Av. Bento Gonçalves 9500, CEP-91501-970, Porto Alegre, Rio Grande do Sul - RS 15051, Brazil.
Jocenir
J
Boita
Laboratório de Espectroscopia de Elétrons (LEe-), Instituto de Física, Universidade Federal do Rio Grande do Sul (UFRGS), Av. Bento Gonçalves 9500, CEP-91501-970, Porto Alegre, Rio Grande do Sul - RS 15051, Brazil.
Marcus Vinicius
MV
Castegnaro
Instituto de Química, Universidde Federal do Rio Grande do Sul (UFRGS), Av. Bento Gaonçalves 9500, CEP-91501-970, Porto Alegre, Rio Grande do Sul - RS 15003, Brazil.
Maria do Carmo Martins
Mdo C
Alves
Laboratório de Espectroscopia de Elétrons (LEe-), Instituto de Física, Universidade Federal do Rio Grande do Sul (UFRGS), Av. Bento Gonçalves 9500, CEP-91501-970, Porto Alegre, Rio Grande do Sul - RS 15051, Brazil.
Jonder
J
Morais
DXAS; in situ XAS; instrumentation; nanoparticles; platinum; synthesis