Composite Electrocatalyst Derived from Hybrid Nitrogen-Containing Metal Organic Frameworks and g-C3N4 Encapsulated InSitu into Porous Carbon Aerogels

A novel composite Fe-bpdc-C3N4-CA catalyst (where bpdc stands for 2,2'-bipyridine-3,3'-dicarboxylic acid and CA stands for carbon aerogel) with a high nitrogen content was synthesized through the insitu encapsulation of nitrogen-containing metal organic frameworks along with g-C3N4 into porous CAs. The characteristics of the catalysts calcined at different temperatures were determined by means of TEM, XRD, Raman spectroscopy, XPS, and BET measurements. The results demonstrate the successful doping of N heteroatoms and the effective formation of Fe-N-X active sites. The electrocatalytic properties were investigated by using rotating disk electrode (RDE) and rotating ring disk electrode (RRDE) measurements. The Fe-bpdc-C3N4-CA catalyst calcined at 800 degrees C exhibits the highest oxygen reduction reaction activity with the initial reduction potential and half-wave potential reaching 1.09 and 0.96V, respectively, versus RHE in 0.1M KOH. It also possesses high stability and follows approximately a complete four-electron (4e(-)) reaction pathway, as commercial Pt/C catalysts do.