Boosting Oxygen Reduction Catalysis with Hierarchically Porous Fe-Doped Carbon by Chemical Vapor Deposition in Zn–Air Batteries

Abstract

The effective application of Fe–N-doped carbon as an oxygen reduction reaction (ORR) electrocatalyst for advanced electrochemical devices has long been impeded by the design and preparation of high-performance electrodes. Herein, we developed a class of carbon-based electrocatalysts through a wet chemistry strategy and the chemical vapor deposition (CVD) method. A great deal of Zn species with a low boiling point evaporate outward to generate abundant micropores, while the Fe dopant is essential for constructing large-sized nanopores attributable to the Kirkendall effect. The CVD-assisted material possesses a higher quantity of uniformly distributed Fe–N x active sites and a larger specific surface area with hierarchically porous nanostructures compared to the electrocatalyst prepared by the wet chemistry strategy. The resulting FeNC-CVD displays satisfactory electrocatalytic ORR performance with high half-wave potential (0.88 V), outperforming that of commercial Pt/C (0.86 V). As expected, the Zn–air batteries assembled by FeNC-CVD achieve an outstanding peak power density and robust discharge platforms, manifesting the bright application prospect of the attractive electrocatalyst in advanced energy devices. This work may provide new perception on boosting the rational design and indepth understanding of CVD-assisted materials.

Hierarchically porous N-doped carbon nanosheets with atomically dispersed Fe/Co dual-metallic sites for efficient and robust oxygen electrocatalysis in Zn–air batteries

“…5,[12][13][14][15][16][17] Among the Fe-N-C catalysts, single Fe atoms coordinated with nitrogen (Fe-N x ) moieties are commonly identified as the real catalytic sites for absorbing O 2 and accelerating the subsequent ORR kinetics. [18][19][20][21] To further boost the ORR activities of Fe-N-C catalysts, several strategies have been developed, including increasing the exposed Fe-N x active sites, modulating the local coordination environments of central metal atoms, and incorporating another active metal atom to generate bimetal-N-C species. 14,[22][23][24][25][26] Among them, the unique bimetal-N-C species can not only offer more favorable M-N x active sites but also create fantastic synergistic effects to break the bond in O 2 during ORR, significantly boosting the electrocatalytic activities.…”