RT journal article
T1 Influence of {111} nanofaceting on the dynamics of CO adsorption and oxidation over Au supported on CeO2 nanocubes: An operando DRIFT insight
A1 Fernández García, Susana
A1 Collins, Sebastían E.
A1 Tinoco Rivas, Miguel
A1 Hungría Hernández, Ana Belén
A1 Calvino Gámez, José Juan
A1 Cauqui López, Miguel Ángel
A1 Chen, Xiaowei
A2 Ciencia de los Materiales e Ingeniería Metalúrgica y Química Inorgánica
K1 Ceria
K1 Ceria
K1 Gold
K1 Nanocubes
K1 DRIFT c-MES
K1 CO oxidation
AB CO adsorption and further reaction with O2 on two Au/CeO2 model systems have been investigated by operandodiffuse reflectance infrared Fourier transform spectroscopy (DRIFT) in order to unveil the active sites for COoxidation. One of the ceria supports was constituted by crystallites depicting a nanocube shape bounded mostlyby {100} planes, whilst the second one was consisted of nanocubes whose {110} surfaces were reconstructedinto {111}-nanofacets with a zig-zag shape. The deconvolution of the CO adsorption bands and a detailedanalysis of the time-evolution of these bands were also carried out. These studies evidenced a fast adsorption ofCO over Au° and then Auδ--CO bands appeared during exposure to CO, in parallel with the appearance of Ce3+features. Such changes suggest that CO adsorption process starts on Au sites on the low coordinated sites of thesurface of the Au nanoparticles and their transfer to the interface sites. By comparing the nanostructure of thetwo catalysts, the Auδ--CO species could be fruitfully related to CO adsorption on sites located at the Au||CeO2perimeter. The sample containing gold nanoparticles dispersed over the {111}-nanofaceted CeO2 nanocubes,which retained a higher amount of gold nanoparticles, depicts higher contribution of Auδ−−CO bands than theother Au catalyst in the DRIFT spectra. The dynamic DRIFT study clearly revealed that the CO species adsorbedon Auδ- sites were the most reactive ones in both gold supported systems for CO oxidation. This explains muchhigher TOF values observed on the catalyst prepared on the surface reconstructed support. A detailed analysis onthe reactivity was performed by modulation excitation spectroscopy (MES). The presence of peroxide surfacespecies (O22-) in nanofaceted {111} could lead to higher catalytic activity than that of gold on the non-reconstructedcatalyst.
SN 0920-5861
YR 2019
FD 2019-01
LK http://hdl.handle.net/10498/30001
UL http://hdl.handle.net/10498/30001
LA eng
DS Repositorio Institucional de la Universidad de Cádiz
RD 07-nov-2026