Three-Dimensional Biocarbon Framework Coupled with Uniformly Distributed FeSe Nanoparticles Derived from Pollen as Bifunctional Electrocatalysts for Oxygen Electrode Reactions.

The development of carbon-based catalysts with satisfactory performance for the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) is critical but challenging to achieve sustainable energy conversion and storage. Herein, a pollen biomass-derived carbon electrocatalyst with a three-dimensional porous framework, coupled with uniform distribution of FeSe nanoparticles, has been prepared by pyrolysis of the pollen precursor, followed by selenylation. The optimal catalyst FeSe/NC-PoFeSe exhibits a superb ORR activity with a half-wave potential of 0.86 V versus a reversible hydrogen electrode and OER activity with a low overpotential (330 mV at 10 mA cm-2 ) in alkaline media, compared with commercial Pt/C and IrO2 /C catalysts, respectively. On the basis of the characterization results, we ascribe the enhanced ORR performance to sufficient Fe-N x , pyridinic N, and graphitic N and the excellent OER performance in the presence of FeSe nanoparticles uniformly mounted on the N-doped carbon materials. In addition, we believe that the coupling effect between the FeSe nanoparticles and biocarbon led to a further improvement in the electrochemical performance. Significantly, the prominent ORR and OER stability of FeSe/NC-PoFeSe shows great promise in renewable energy devices.