A high performance non-noble metal electrocatalyst for the oxygen reduction reaction derived from a metal organic framework

The development of a non-precious metal electrocatalyst (NPME) with a performance superior to commercial Pt/C for the oxygen reduction reaction (ORR) is important for the commercialization of fuel cells. We report the synthesis of a NPME by heat-treating Co-based metal organic frameworks (ZIF-67) with a small average size of 44 nm. The electrocatalyst pyrolyzed at 600 °C showed the best performance and the performance was enhanced when it was supported on BP 2000. The resulting electrocatalyst was composed of 10 nm Co nanoparticles coated by 3–12 layers of N doped graphite layers which as a whole was embedded in a carbon matrix. The ORR performance of the electrocatalyst was tested by rotating disk electrode tests in O2-saturated 0.1 mol/L KOH under ambient conditions. The electrocatalyst (1.0 mg/cm2) showed an onset potential of 1.017 V (vs. RHE) and a half-wave potential of 0.857 V (vs. RHE), which showed it was as good as the commercial Pt/C (20 μgPt/cm2). Furthermore, the electrocatalyst possessed much better stability and resistance to methanol crossover than Pt/C.

Graphical AbstractWe reported the synthesis of a NPME by heat-treating cobalt-based metal organic frameworks (ZIF-67, with a small size of 44 nm) from 500–900 °C. The electrocatalyst pyrolyzed at 600 °C showed the best performance and the performance was enhanced when it was supported on BP 2000.Figure optionsDownload full-size imageDownload as PowerPoint slide