charged), while carbonyl oxygen is adsorbed on Ir ones (positively charged;
Fig. 12b).
6.2.2 Ir NPs Supported on ZrO 2
ZrO 2, or zirconia, is also a metal oxide support suitable for MNP stabilisation due to
its high surface area and good thermal stability. For example, in 2010, Ir NPs
supported on hydrous zirconia (Ir/ZrO 2• xH 2 O) were straightforwardly prepared by
a co-precipitation method by Li et al [112]. This catalyst, Ir/ZrO 2• xH 2 O, compared
with Ir/ZrO 2 prepared by impregnation method, showed a higher activity and
selectivity in the hydrogenation of haloaromatic nitro compounds to the
Fig. 11 (a) Cyclohexene hydrogenation to cyclohexane and dehydrogenation to benzene over
Ir/NT, Pt/NT and PtIr/NT catalysts. (b) Selectivity to cyclohexane and benzene. Reprinted with
permission from Ref. [110]. Copyright 2012 Elsevier
Fig. 12 (a) Hydrogenation of cinnamaldehyde over Au/TiO 2 , Ir/TiO 2 and Au-Ir/TiO 2 . (b) Adsorption mode of cinnamaldehyde on Au-Ir/TiO 2 proposed by Li et al. Reprinted with permission from
Ref. [111]. Copyright 2014 Elsevier
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