Support nitrogen-doped carbon materials

Nitrogen-doped carbon materials shows good catalysts support in terms of catalytic activity and stability [18,19]. A graphitic carbon nitride with three-dimensionally extended highly ordered pore arrays has been reported as a support for a Pt-Ru alloy catalyst of a DMFC anode. The nanostructured C3N4 has 73-83% higher power density than Vulcan XC-72, a commercial carbon black. 

CoSe2 nanomaterials have also been prepared as catalysts for nitrogen doped carbons as low cost materials. The carbon supports were synthesised by pyrolysis of vulcan, which was coated with carbon and nitrogen precursors with formaldehyde and ethylene diamine or 1,6-diaminohexane being the carbon and nitrogen sources respectively. To load the CoSca layer dicobalt octacarbonyl and nitrogen doped carbon were mixed with 200 ml dehydrated jylene. The carbonyl sol was then refluxed for 2 h at 140 °C in a four neck flask with nitrogen protection. 

It is known that the efficiency of catalysts is not only a function of the kind of active site, but also dependent on the constimtion of the carbon support, that will influence the overall electronic properties of the catalyst material [96, 107-109]. For platinum-based catalysts, it was shown that by nitrogen doping of the carbon support, the platinum particles are stronger linked to the support material compared to the not-modified carbon. The resultant smaller particles with a more homogeneous distribution enabled higher ORR activity and an improved long-term stability [107, 110]. 

Diamond is sp hybridized with a C-C bond of 1.54 A and has very low intrinsic conductivity, considered a wide-bandgap semiconductor (5.5 eV). Doping is required to increase the conductivity to a level sufficient to support electrochemical measuranents. Boron, a p-type dopant, is the most common element used, but nitrogen is also used as an n-type dopant. Doped diamond materials, such as boron-doped diamond (BDD), are chemically inert and can often display a wider potential window than other carbon electrodes. NanocrystaUine diamond (NCD) contains significant sp character due to defects, which increase the material s conductivity without additional doping. The Raman band at 1332 cm is associated with the sp diamond lattice. The intensities of the sp band and the D-band for sp carbons at 1360 cm" can be used to determine the relative amounts of sp impurities in diamond, but the cross section for the D-band is approximately 50 times larger than that for diamond. ... 

The doped nitrogen atoms not only provide the anchoring sites for the metal particles but also act as chemically active sites for fuel cell reactions. The N sites in N-CNTs are reported to bind strongly to metals, leading to excellent metal dispersion in metal/N-CNT materials. The surface modifications induced in CNTs by N doping can thus enhance the reactivity and selectivity of carbon-supported catalysts in many catalytic applications [33]. Therefore, it should be possible to avoid functionalization processes that use strong acid treatments, as it is relatively easy to deposit metal catalysts onto N-CNTs [33]. 

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