Activity of CO oxidation

The surface imperfections in Ru(OOOl) from mechanical polishing appear responsible for a sizable activity of CO oxidation that resulted in the spectra with peaks around 2346, 2010, and 1780 cm They correspond to CO2 in solution, COl and COh, respectively Fig. 13. Interestingly, in the FTIR spectra for the... 

From these analyses, it was found that the 2 nm thick Ir layer had a hetero-junction between the rutile TiOz surface and the large surface area of the exposed Ir metal surface, due to the thin layered structure of Ir. Our work therefore suggests that the activity of CO oxidation was directly associated with the structure of the Ir metal phase having nano-level thickness on the TiOz support, and the selection of the support. 

Oxidation. Oxidation of CO was studied on a number of metal nitrides at 573 K, and the following sequence of activity per surface area was found Fe2N > CrN> VN > ZrNo.7 > ZrN (112). Nonstoichiometric compounds were found to be more active than their stoichiometric counterparts, probably because they had cleaner surfaces. For the same metal, nitrides were slightly more active than carbides, which were now much more active than borides. Recently, high surface area M02N powders were found to exhibit high catalytic activity of CO oxidation at 723 K (113). 

Park JY, Zhang Y, Joo SH, Jung Y, Somoijai GA (2012) Size effect of RhPt bimetallic nanoparticles in catalytic activity of CO oxidation role of surface segregation. Catal Today 181 133-137. doi 10.1016/j.cattod.2011.05.031... 

Park J, Aliaga C, Renzas JR, Lee H, Somorjai G (2009) The role of organic capping layers of platinum nanoparticles in catalytic activity of CO oxidation. Catal Lett 129 1-6... 

Qadir K, Kim SH, Kim SM, Ha H, Park JY (2012) Support effect of arc plasma deposited Pt nanoparticles/Ti02 substrate on catalytic activity of CO oxidation. J Phys Chem C 116 24054-24059... 

Role of Surface Oxides on Model Nanocatalysts in Catalytic Activity of CO Oxidation... 

In conclusion, these observations show that the surface oxide formed on Pt crystal surfaces and on Pt nanoparticles is catalytically active for the CO oxidation reaction. Whether the oxidized Pt surface is catalytically active, however, is still up for some debate. Therefore, studies to bridge the connection between surface structures and catalytic performance are now needed to clearly understand how surface oxide layers affect the catalytic activity of CO oxidation. 

Catalytic Activity of CO Oxidation on Ru Nanoparticles and Ru Oxides Probed with Ambient Pressure XPS... 

In this chapter, we reviewed the role of surface oxide on Pt, Rh, Ru, and Pd nanoparticles, and showed that surface oxide plays an important role in the catalytic activity of CO oxidation. Increasing evidence shows that Pt oxide and Rh oxide are reactive species, while Ru bulk oxide is not reactive. Catalytic activity increases as the size of the Ru nanoparticles increases and as the size of the Rh nanopardcles decreases. AP-XPS studies indicate that the change in catalytic activity is correlated with the formation of surface oxide. Surface treatments, such as UV-ozone treatment, facilitate oxide layer engineering, which changes the catalytic activity. The active surface oxide on Rh NPs, formed after UV-ozone treatment, leads to increased catalytic activity. On the other hand, the inactive surface oxide on Ru NPs, formed by UV-ozone treatment, caused the catalytic activity to deaease. These results suggest an intriguing way to tune the catalytic activity of metal catalysts by engineering the surface oxide layer. 

Qadir K, loo SH, Mun BS, Butcher DR, Renzas JR, Aksoy F, Liu Z, Somorjai GA, Park JY (2012) Intrinsic relation between catalytic activity of CO oxidation on Ru nanoparticles and Ru oxides uncovered with ambient pressure XPS. Nano Lett 12 5761-5768... 

Effect of electrochemical properties of perovskite catalyst on CO oxidation reaction was recently investigated through comparing with CH4 complete oxidation reaction, which is usually considered to be an intrafacial reaction. Results indicate that for suprafacial CO oxidation, its activity depends mainly on the redox peak area of the catalyst, while for intrafacial CH4 oxidation, the activity depends on the symmetry of redox potentials of the catalyst. [65, 66] Dependence of CO oxidation activity on the redox peak area was shown in Figure 8, which clearly showed that they have the same trends, indicating that the redox peak area of catalyst is a very important parameter in deciding the activity of CO oxidation. 

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