Adsorption on Semiconductor Oxides

Catalyst Reduction temperature (K) H2 uptake (pmoles) Dispersion (%) Particle diameter dp (ran) 

The obtained molar ratio of CO/H2 for the P1/A1203 can be justified, since CO adsorbs as linear (CO/H2 = 2) and bridged forms (CO/H2 =1). However, for the Pt-Zr02, this ratio is very high and means interaction of Pt-CO at the interface of Pt-ZrOx, since the amount of CO adsorbed on zirconia is very low. 

The results of the irreversible hydrogen adsorption oti the C0/AI2O3 and Co/Nb20s were obtained, according to the procedures described before [29] and are shown in Table 4.6. 

Noteworthy is that the H2 adsorption on Co alumina support is independent of the reduction temperatiue and, however, shows great effect on the Co niobia support, provoking significant decrease of adsorption with increasing reduction temperature suggesting strong metal-support interactiOTi effects [29]. 

Semiconductors are the most used in catalysis. The semiconductors have conductivity of the order of 10 a 10 Q/cm and can be classified as intrinsic or extrinsic semiconductors, also considered as nonstoichiometric materials. The extrinsic semiconductors are natural materials [4]. 

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