Environmental Engineering Reference
In-Depth Information
35
30
25
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35
Pd
Ag
Pt
Cu
Au
10
5
0
0
200
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600
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t (S)
Figure 8.18 h e activity of dif erent metal particles in glucose oxidation. [Metal] = 10 -4
M, [glucose] = 0.4 M, T = 303 K. Reproduced with permission from [98].
Baatz et al. demonstrate that the preparation of gold catalyst (size < 2 nm)
for liquid phase glucose oxidation by the incipient wetness method has
some advantages over the DP urea method, even at high gold loading [99].
A traditional method was optimized by Pruesse et al. [100] for preparing
an ei cient catalyst for glucose oxidation, based on the impregnation of the
active component onto the support (0.3% Au/Al 2 O 3 ).
Early reports using heterogeneous catalysts demonstrated the use of
platinum on carbon as a catalyst for selective oxidation of glucose reac-
tion; however, it was found that these catalysts suf ered from deactivations,
which were decreased when the reaction was carried out at high pH, but
catalyst deactivation could not eliminated. Maintaining the pH at 9 elimi-
nated the deactivation, suggesting that the deactivation observed could
be due to a poisoning ef ect from competitive adsorption of one of the
reaction components. However, the use of bimetallic catalysts for the glu-
cose oxidation reaction was i rst reported by Besson et al. h ey used Bi-Pd
supported on carbon and got the conversion close to 100%. Wenkin et al.
carried out an extensive study into the preparation of carbon-supported
bismuth-promoted palladium catalysts for glucose oxidation, but they
found in each case that leaching of bismuth into the reaction solution was
detected for all the catalysts tested.
Biella et al. proposed the use of gold supported on carbon prepared
by the sol-immobilization method for this oxidation. It was found that
gold catalysts were more active than platinum, palladium-bismuth or
platinum-palladium-bismuth trimetallic catalysts. h e gold was also
 
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