Enhancing Electrocatalytic Oxygen Reduction on Nitrogen-Doped Graphene by Active Sites Implantation

Abstract

The shortage of nitrogen active sites and relatively low nitrogen content result in unsatisfying eletrocatalytic activity and durability of nitrogen-doped graphene (NG) for oxygen reduction reaction (ORR). Here we report a novel approach to substantially enhance electrocatalytic oxygen reduction on NG electrode by the implantation of nitrogen active sites with mesoporous graphitic carbon nitride (mpg-C3N4). Electrochemical characterization revealed that in neutral electrolyte the resulting NG (I-NG) exhibited super electrocatalytic activity (completely 100% of four-electron ORR pathway) and durability (nearly no activity change after 100000 potential cyclings). When I-NG was used as cathode catalyst in microbial fuel cells (MFCs), power density and its drop percentage were also much better than the NG and Pt/C ones, demonstrating that the current I-NG was a perfect alternative to Pt/C and offered a new potential for constructing high-performance and less expensive cathode which is crucial for large-scale application of MFC technology.

Electrochemical stability of the polymer-derived nitrogen-doped carbon: an elusive goal?

“…From the LSV (Fig. 3b), the current at -0.45 V for the fresh electrode drops for about 38 % after 2,000 cycles, which is significant loss when compared to previous reports [36]. Since there is a lack of standardized protocol of the durability test for the alkaline ORR catalyst as well as a lack of reliable information with regards to the stability of polypyrrole-derived N-doped carbon we can conclude that the rapid electrochemical degradation of our materials originates from the low content of graphitized carbon and from the minor amount of graphitic N-C structures.…”

“…The electrochemical stability of the N-doped carbon catalyst is still unclear with some groups claiming the N-doped C is stable thermally and chemically [34], electrochemically in both acidic [35] and alkaline medium [36], and the loss of electrochemical performance under extensive potential cycling is only related to the delamination of the catalyst layer (mechanical instability) [37]. After careful observation, we concluded that most studies dealing with the electrochemical durability of N-doped carbons are carried out for the N-doped graphitized structures, such as N-CNs [17] or N-doped graphene [38], and correlate the superior stability with the presence of substantial amount of quaternary and graphitic N-C structures (Fig.…”

Controlling the Incorporation of Phosphorus Functionalities on Carbon Nanofibers: Effects on the Catalytic Performance of Fructose Dehydration

“…The introduction of heteroatoms (N, O, P, and S) has been reported to confer higher hydrophilicity, enhanced metal-support interactions, and additional acidic or basic sites [23][24][25][26][27][28][29][30][31][32]. Obviously, the distribution, the amount, the location, and the specific binding forms of the heteroatoms on the surface strictly depend on the nature of the carbonaceous substrate.…”

Application of Graphene‐Based Materials to Improve Electrode Performance in Microbial Fuel Cells

“…A simple way to increase the content of pyridinic N and pyrrolic N is to increase the total number of nitrogen active sites. It was found that the implantation of nitrogen active sites to NG (I-NG) with mesoporous g-C 3 N 4 introduced a large number of nitrogen sites on the surface of NG (Figure 13.6) [44]. I-NG with high content nitrogen has the strong ability of weakening the O-O bond via the bonding between oxygen and nitrogen, and the MFC using I-NG as a cathode catalyst produced a much higher power density than the normal NG MFC and even Pt/C MFC [44].…”