Insight into the nitrogen-doped carbon as oxygen reduction reaction catalyst: The choice of carbon/nitrogen source and active sites

Nitrogen doped graphitic carbon ribbons from cellulose as non noble metal catalyst for oxygen reduction reaction

“…Many novel energy sources have been developed, one of which is the hydrogen energy [1]. Fuel cells are electric generators to make use of the hydrogen energy with lots of advantages such as high efficiency and environmentally friendly.…”

Post‐formation Copper‐Nitrogen Species on Carbon Black: Their Chemical Structures and Active Sites for Oxygen Reduction Reaction

“…In this figure, there are not any diffraction peaks for Cu nanoparticles or Cu‐based compounds, besides the diffraction peaks around 24° and 44° that are assigned to (0 0 2) and (1 0 1) lattice plane of carbon, respectively . In addition, compared with the CB and N‐C, the Cu‐N‐C sample shows a shifted diffraction peak, assigned to the (0 0 2) lattice plane, to the higher angle direction, indicating the incorporation of foreign atoms into the sample . Furthermore, the specific surface area and pore‐size distribution were determined for the Cu‐N‐C sample.…”

“…[13] In addition, compared with the CB and N-C, the Cu-N-C sample shows as hiftedd iffraction peak, assigned to the (0 02)l attice plane, to the higher angle direction, indicating the incorporationo ff oreign atoms into the sample. [14] Furthermore, the specific surfacea rea and pore-size distribution wered etermined for the Cu-N-C sample. As shown in Figure 1(h) and (i), its Brunauer-Emmett-Teller (BET) specific surfacea rea is 256.77 m 2 g À1 ,a nd it exhibits ap ore-size distributionr anging from 0.75 to 6.50 nm, whichi ss imilar to those of the CB or N-C samples.…”

“…Figure (d) shows the Tafel plots of the Cu‐N‐C and Pt/C catalyst in the low‐overpotential region, where the overall ORR rate is dependent on the surface reaction rate on the catalyst . The recorded Tafel slope for the Cu‐N‐C is 63 mV dec −1 , very close to that for the Pt/C catalyst (62 mV dec −1 ), demonstrating that the Cu‐N‐C and Pt/C catalyst share the similar rate‐determining step, which is the first electron reduction of oxygen to form adsorbed intermediates on the surface of the catalyst …”

“…[9] The recorded Tafel slope for the Cu-N-C is 63 mV dec À1 ,v ery close to that for the Pt/C catalyst( 62 mV dec À1 ), demonstrating that the Cu-N-C and Pt/C catalysts hare the similar rate-determining step, which is the first electron reduction of oxygen to form adsorbedi ntermediates on the surfaceofthecatalyst. [4,14] Besides the electrocatalytic activity,t he ORR pathway on the Cu-N-Cc atalysts hould be explored, because the oxygen reductioni nvolvesacomplexm ulti-stepp rocess. [3] Based on the disk and ring currents shown in Figure 5(a), the number of transfer electron (n)a nd the HO 2 À yield on the Cu-N-Ca nd commercial Pt/C catalysta re given in Figure 5(b).…”