Influence of nitrogen and iron precursors on the synthesis of FeNx/carbons electrocatalysts toward oxygen reduction reaction in acid solution

Synthesis of FeCo–N@N-doped carbon oxygen reduction catalysts via microwave-assisted ammoxidation

A core–shell structured FeCo–N@N-doped carbon derived from biomass wastes (sugarcane and palm kernel shell) is facilely prepared by hydrothermal carbonization and NH₃ microwave ammoxidation methods.

Synergistic Effect of Molecular-Type Electrocatalysts with Ultrahigh Pore Volume Carbon Microspheres for Lithium-Sulfur Batteries

Lithium-sulfur (Li-S) batteries are regarded as potential high-energy storage devices due to their outstanding energy density. However, the low electrical conductivity of sulfur, dissolution of the active material, and sluggish reaction kinetics cause poor cycle stability and rate performance. A variety of approaches have been attempted to resolve the above issues and achieve enhanced electrochemical performance. However, inexpensive multifunctional host materials which can accommodate large quantities of sulfur and exhibit high electrode density are not widely available, which hinders the commercialization of Li-S batteries. Herein, mesoporous carbon microspheres with ultrahigh pore volume are synthesized, followed by the incorporation of Fe-N-C molecular catalysts into the mesopores, which can act as sulfur hosts. The ultrahigh pore volume of the prepared host material can accommodate up to ∼87 wt % sulfur, while the uniformly controlled spherical morphology and particle size of the carbon microspheres enable high areal/volumetric capacity with high electrode density. Furthermore, the uniform distribution of Fe-N-C (only 0.33 wt %) enhances the redox kinetics of the conversion reaction of sulfur and efficiently captures the soluble intermediates. The resulting electrode with 5.2 mg sulfur per cm² shows excellent cycle stability and 84% retention of the initial capacity even after 500 cycles at a 3 C rate.

Iron-nitrogen-activated carbon as cathode catalyst to improve the power generation of single-chamber air-cathode microbial fuel cells

In order to improve the performance of microbial fuel cell (MFC), iron-nitrogen-activated carbon (Fe-N-C) as an excellent oxygen reduction reaction (ORR) catalyst was prepared here using commercial activated carbon (AC) as matrix and employed in single chamber MFC. In MFC, the maximum power density increased to 2437±55 mW m(-2), which was 2 times of that with AC. The open circuit potential (OCP) of Fe-N-C cathode (0.47) was much higher than that of AC cathode (0.21 V). The R0 of Fe-N-C decreased by 47% from 14.36 Ω (AC) to 7.6 Ω (Fe-N-C). From X-ray photoelectron spectroscopy (XPS), pyridinic nitrogen, quaternary nitrogen and iron species were present, which played an important role in the ORR performance of Fe-N-C. These results demonstrated that the as-prepared Fe-N-C material provided a potential alternative to Pt in AC air cathode MFC for relatively desirable energy generation and wastewater treatment.

Iron nanoparticles with a square pyramidal structure in mesoporous carbons as an effective catalyst toward oxygen reduction

FeAMC-1273, with more pyridinic-N and pyridinic-N–Fe for the creation of a square pyramidal planar geometry around iron, exhibits the best ORR activity.