Factors Affecting the Performance of a Carbon Catalyst

Oxygenated functions have been studied most extensively, since they are formed spontaneously by exposure of the carbon material to the atmosphere. The concentration of these groups can be increased further by oxidative treatments, in 

The concentration of active sites depends to a large extent on the microcrystalline structure of the carbon material. Small crystallites can expose more edges therefore, more surface groups can be formed, while the role of the basal planes and the K electrons will become more important with large crystallites. Thus, the orientation of the graphene layers and the ratio between prismatic and basal plane areas may affect the catalytic performance, and such effects have indeed been reported in the case of carbon nanohbers (see Section 6.3.1). 

The concentration of the relevant surface functional groups can be determined by the methods described in Chapter 2. Temperature-programmed desorption (TPD) seems to be the best method to determine the concentration of oxygen groups, especially in the case of porous carbons [21,37-41], and x-ray photoelectron spectroscopy (XPS) is the method used to determine the concentration of nitrogen functions (see Chapter 7). 

---