Atomic Fe-Doped MOF-Derived Carbon Polyhedrons with High Active-Center Density and Ultra-High Performance toward PEM Fuel Cells
Abstract
A metalorganic gaseous doping approach for constructing nitrogen-doped carbon polyhedron catalysts embedded with single Fe atoms is reported. The resulting catalysts are characterized using scanning transmission electron microscopy, X-ray photoelectron spectroscopy, and X-ray absorption spectroscopy; for the optimal sample, calculated densities of Fe-Nx sites and active N sites reach 1.75812 × 1013 and 1.93693 × 1014 sites cm-2, respectively. Its oxygen reduction reaction half-wave potential (0.864 V) is 50 mV higher than that of 20 wt% Pt/C catalyst in an alkaline medium and comparable to the latter (0.78 V vs 0.84 V) in an acidic medium, along with outstanding durability. More importantly, when used as a hydrogen-oxygen polymer electrolyte membrane fuel cell (PEMFC) cathode catalyst with a catalyst loading as low as 1 mg cm-2 (compared with a conventional loading of 4 mg cm-2), it exhibits a current density of 1100 mA cm-2 at 0.6 V and 637 mA cm-2 at 0.7 V, with a power density of 775 mW cm-2, or 0.775 kW g-1 of catalyst. In a hydrogen-air PEMFC, current density reaches 650 mA cm-2 at 0.6 V and 350 mA cm-2 at 0.7 V, and the maximum power density is 463 mW cm-2, which makes it a promising candidate for cathode catalyst toward high-performance PEMFCs.
- Publication:
-
Advanced Energy Materials
- Pub Date:
- April 2019
- DOI:
- 10.1002/aenm.201802856
- Bibcode:
- 2019AdEnM...902856D