Oxygen Reduction Reaction Studies of Phosphorus and Nitrogen Co‐Doped Mesoporous Carbon Synthesized via Microwave Technique

Abstract

Metal‐free mesoporous P and N co‐doped carbon (PNDC) composites are evaluated for their electrocatalytic activity towards the oxygen reduction reaction (ORR). Carbonization of melamine and hexamine‐modified tannin in the presence of polyphosophoric acid produces PNDCs with prominent oxygen reduction properties in alkaline media. The effect of the P and N content in the carbon material is evaluated in terms of the ORR activity. The compound containing a high amount of N (8.3 atom %) and P (6.8 atom %), denoted PNDC‐1, shows high electrocatalytic activity, stability, durability, and selectivity towards the ORR. PNDC‐1 has an onset potential of 0.10 V versus a reversible hydrogen reference electrode and shows a significantly improved performance in comparison to the carbon materials containing less P and N dopant atoms. PNDCs exhibit superior ORR current densities to that of the 20 % Pt/C catalyst because of the synergetic effect of P and N co‐doping. X‐ray photoelectron spectroscopy studies indicate the presence of pyridinic and graphitic N species, which are responsible for oxygen reduction that results in higher current densities. Rotating disk electrode and rotating ring‐disk electrode studies support a four electron oxygen reduction to water, with negligible generation of hydrogen peroxide.

Chitosan Waste‐Derived Co and N Co‐doped Carbon Electrocatalyst for Efficient Oxygen Reduction Reaction

“…M–N–C catalysts show excellent performance for the ORR, owing to their specific metal–nitrogen (M–N) bonds, which play crucial roles in oxygen reduction . Unfortunately, recent research on M–N–C catalysts has mainly been focused on the pyrolysis of the carbon materials with nitrogen sources and metal salts (nitrates or chlorides) . These methods always suffer from complicated preparation methods, uncontrollable generation of the metal oxides, and agglomeration of the metal nitrides in the carbon matrix.…”

Heteroatom‐Doped Carbon Materials for Electrocatalysis

“…Recently, additional reports have revealed that the incorporation of two or more types heteroelement dopants into carbon materials could create large numbers of active sites favorable for electrocatalysis . In fact, some of these bi‐ and tridoped carbon materials (for example, N and S; B and N; or N and P co‐doped carbons) show better catalytic performances toward ORR than their singly‐doped counterparts, and in some cases, better activities than even Pt/C (20 %) . They also often show much better stability than Pt/C catalysts .…”

“…As mentioned above, carbon materials doped with multiple types of dopants (e.g., N and B; N and P; N and S; N, P and S; etc.) often show high electrocatalytic activities ,. Synthetic methods that can provide multi‐doped carbon materials with not only high dopant density but also uniformly distributed multi‐element dopants are, however, lacking.…”

Tuning Cobalt and Nitrogen Co‐Doped Carbon to Maximize Catalytic Sites on a Superabsorbent Resin for Efficient Oxygen Reduction

“…[4] In view of this, extensive research efforts have been carried out to overcome these problems, including the synthesis of noble-metal/transition-metal (such as Fe, Co, Cu, and Ni)a lloys with special structuralc ontrol [4a, 5] and entirely new non-noble-metal materials doped with the active elements, such as metal-free heteroatom-doped carbon materials, [1c, 6] transition-metal/nitrogen-doping carbon materials (M-N x -C), [7] transition-metal nitrides, [8] oxides, [9] and sulfides, [10] as well as their hybrids, [7b, 11] etc. [12] The major one is the thermal treatment strategy of precursors with the help of as ol-gel technique, [13] the template method, [14] and in situ synthesis [15] .T he second aspectf ocuseso nn ew strategies, involving chemical vapor deposition, [16] the wet-chemical strategy, [17] microwave methods, [18] etc. [12] The major one is the thermal treatment strategy of precursors with the help of as ol-gel technique, [13] the template method, [14] and in situ synthesis [15] .T he second aspectf ocuseso nn ew strategies, involving chemical vapor deposition, [16] the wet-chemical strategy, [17] microwave methods, [18] etc.…”