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Gold nanoparticles supported on magnesium oxide for CO oxidation.

Carabineiro SA, Bogdanchikova N, Pestryakov A, Tavares PB, Fernandes LS, Figueiredo JL - Nanoscale Res Lett (2011)

Bottom Line: Samples were characterised by adsorption of N2 at -96°C, temperature-programmed reduction, high-resolution transmission electron microscopy, energy-dispersive X-ray spectroscopy and X-ray diffraction.CO oxidation was used as a test reaction to compare the catalytic activity.This can be explained in terms of the nanoparticle size, well known to determine the catalytic activity of gold catalysts.

View Article: PubMed Central - HTML - PubMed

Affiliation: Laboratório de Catálise e Materiais, Departamento de Engenharia Química, Faculdade de Engenharia, Universidade do Porto, 4200-465 Porto, Portugal. scarabin@fe.up.pt.

ABSTRACT
Au was loaded (1 wt%) on a commercial MgO support by three different methods: double impregnation, liquid-phase reductive deposition and ultrasonication. Samples were characterised by adsorption of N2 at -96°C, temperature-programmed reduction, high-resolution transmission electron microscopy, energy-dispersive X-ray spectroscopy and X-ray diffraction. Upon loading with Au, MgO changed into Mg(OH)2 (the hydroxide was most likely formed by reaction with water, in which the gold precursor was dissolved). The size range for gold nanoparticles was 2-12 nm for the DIM method and 3-15 nm for LPRD and US. The average size of gold particles was 5.4 nm for DIM and larger than 6.5 for the other methods. CO oxidation was used as a test reaction to compare the catalytic activity. The best results were obtained with the DIM method, followed by LPRD and US. This can be explained in terms of the nanoparticle size, well known to determine the catalytic activity of gold catalysts.

No MeSH data available.


CO conversion (%): CO conversion (%) versus temperature for MgO supports alone and with Au loaded by different methods (a). Specific activities for the Au/MgO catalysts determined at 25 and at 100°C (b).
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Figure 5: CO conversion (%): CO conversion (%) versus temperature for MgO supports alone and with Au loaded by different methods (a). Specific activities for the Au/MgO catalysts determined at 25 and at 100°C (b).

Mentions: It was found that the activity for CO oxidation (with or without Au) of the heat-treated MgO did not improve when compared with the as-received oxide; therefore, only the results of the untreated samples are shown in Figure 5a. Loading MgO with Au causes total CO conversion to occur at much lower temperatures than with the support alone, as expected. DIM showed to be the best gold-loading method, followed by LPRD and US.


Gold nanoparticles supported on magnesium oxide for CO oxidation.

Carabineiro SA, Bogdanchikova N, Pestryakov A, Tavares PB, Fernandes LS, Figueiredo JL - Nanoscale Res Lett (2011)

CO conversion (%): CO conversion (%) versus temperature for MgO supports alone and with Au loaded by different methods (a). Specific activities for the Au/MgO catalysts determined at 25 and at 100°C (b).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3211853&req=5

Figure 5: CO conversion (%): CO conversion (%) versus temperature for MgO supports alone and with Au loaded by different methods (a). Specific activities for the Au/MgO catalysts determined at 25 and at 100°C (b).
Mentions: It was found that the activity for CO oxidation (with or without Au) of the heat-treated MgO did not improve when compared with the as-received oxide; therefore, only the results of the untreated samples are shown in Figure 5a. Loading MgO with Au causes total CO conversion to occur at much lower temperatures than with the support alone, as expected. DIM showed to be the best gold-loading method, followed by LPRD and US.

Bottom Line: Samples were characterised by adsorption of N2 at -96°C, temperature-programmed reduction, high-resolution transmission electron microscopy, energy-dispersive X-ray spectroscopy and X-ray diffraction.CO oxidation was used as a test reaction to compare the catalytic activity.This can be explained in terms of the nanoparticle size, well known to determine the catalytic activity of gold catalysts.

View Article: PubMed Central - HTML - PubMed

Affiliation: Laboratório de Catálise e Materiais, Departamento de Engenharia Química, Faculdade de Engenharia, Universidade do Porto, 4200-465 Porto, Portugal. scarabin@fe.up.pt.

ABSTRACT
Au was loaded (1 wt%) on a commercial MgO support by three different methods: double impregnation, liquid-phase reductive deposition and ultrasonication. Samples were characterised by adsorption of N2 at -96°C, temperature-programmed reduction, high-resolution transmission electron microscopy, energy-dispersive X-ray spectroscopy and X-ray diffraction. Upon loading with Au, MgO changed into Mg(OH)2 (the hydroxide was most likely formed by reaction with water, in which the gold precursor was dissolved). The size range for gold nanoparticles was 2-12 nm for the DIM method and 3-15 nm for LPRD and US. The average size of gold particles was 5.4 nm for DIM and larger than 6.5 for the other methods. CO oxidation was used as a test reaction to compare the catalytic activity. The best results were obtained with the DIM method, followed by LPRD and US. This can be explained in terms of the nanoparticle size, well known to determine the catalytic activity of gold catalysts.

No MeSH data available.