gy of sols generation appears to be fundamental to obtaining nanoparticles; the support, instead, plays an important role in maintaining particle dimension and morphology. Three different materials (gamma-Al2O3, SiO2 and activated carbon) have been used as the supporting agents for different gold sols that were obtained by reducing HAuCl4 with NaBH4 in the presence of polyvinylalcohol (PVA) or polyvinylpirrolidone (PVP) and with the tetrakis(hydroxymethyl)phosphonium chloride (THPC)/NaOH system. During the immobilisation step, the maintenance of the particle dimension observed in solution depends on both the support and the type of sol. The gold particle mean size of the colloidal suspension is more easily maintained on oxidic supports than on carbon, the latter apparently needing both steric and polar stabilisation of the gold particle. Comparison of Au/gamma-Al2O3 and Au/C catalyst activity in the liquid phase oxidation of ethylene glycol to glycolate highlighted the peculiarity of gold on carbon catalysts; in fact, the normally observed trend of reactivity is partially reversed, medium sized gold particle being the most active.

Metal sols as a useful tool for heterogeneous gold catalyst preparation: reinvestigation of a liquid phase oxidation

COLUCCIA, Salvatore;MARTRA, Gianmario
2000-01-01

Abstract

gy of sols generation appears to be fundamental to obtaining nanoparticles; the support, instead, plays an important role in maintaining particle dimension and morphology. Three different materials (gamma-Al2O3, SiO2 and activated carbon) have been used as the supporting agents for different gold sols that were obtained by reducing HAuCl4 with NaBH4 in the presence of polyvinylalcohol (PVA) or polyvinylpirrolidone (PVP) and with the tetrakis(hydroxymethyl)phosphonium chloride (THPC)/NaOH system. During the immobilisation step, the maintenance of the particle dimension observed in solution depends on both the support and the type of sol. The gold particle mean size of the colloidal suspension is more easily maintained on oxidic supports than on carbon, the latter apparently needing both steric and polar stabilisation of the gold particle. Comparison of Au/gamma-Al2O3 and Au/C catalyst activity in the liquid phase oxidation of ethylene glycol to glycolate highlighted the peculiarity of gold on carbon catalysts; in fact, the normally observed trend of reactivity is partially reversed, medium sized gold particle being the most active.
2000
Inglese
Esperti anonimi
61
165
172
8
metal sols; heterogeneous gold catalyst; liquid phase oxidation
no
1 – prodotto con file in versione Open Access (allegherò il file al passo 6 - Carica)
262
5
F. PORTA; L. PRATI; M. ROSSI; S. COLUCCIA; G. MARTRA
info:eu-repo/semantics/article
reserved
03-CONTRIBUTO IN RIVISTA::03A-Articolo su Rivista
File in questo prodotto:
File Dimensione Formato  
Porta_2000.pdf

Accesso riservato

Tipo di file: PDF EDITORIALE
Dimensione 313.56 kB
Formato Adobe PDF
313.56 kB Adobe PDF   Visualizza/Apri   Richiedi una copia

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/2318/3628
Citazioni
  • ???jsp.display-item.citation.pmc??? ND
  • Scopus ND
  • ???jsp.display-item.citation.isi??? ND
social impact