# Manganese–Iron-Supported Biomass-Derived Carbon Catalyst for Efficient Hydrazine Oxidation

## TL;DR

A new low-cost carbon catalyst made from biomass and iron-manganese is shown to efficiently oxidize hydrazine for use in fuel cells.

## Contribution

A novel, cost-effective MnFe-supported nitrogen-doped carbon catalyst derived from biomass is developed for hydrazine oxidation.

## Key findings

- MnFe/N–C catalysts show higher electrocatalytic activity for hydrazine oxidation than Fe/N–C and MnFe catalysts.
- The catalyst has a highly porous structure with the largest surface area and lowest onset potential.
- The material is a promising anode for direct hydrazine fuel cells.

## Abstract

This study presents a straightforward strategy for producing novel, effective and inexpensive functional non-noble metal-supported carbon materials made from abundant natural biomass. These materials offer a cost-effective alternative to noble metals for the oxidation of hydrazine (HzOR) and demonstrate the potential for widespread adoption of green, energy-saving hydrazine-based technologies in energy applications. Highly efficient and cost-effective iron (Fe) and manganese–iron (MnFe)-supported nitrogen-doped carbon (N–C) materials were developed using hydrothermal synthesis. Meanwhile, the N–C material was obtained from biomass—birch-wood chips—using hydrothermal carbonisation (HTC), followed by activation and nitrogen doping of the resulting hydrochar. The morphology, structure, and composition of the MnFe, MnFe/N–C, and Fe/N–C catalysts were determined using scanning electron microscopy (SEM), X-ray diffraction (XRD), and energy dispersive X-ray spectroscopy (EDS). The activity of the catalysts for HzOR in an alkaline medium was evaluated using cyclic voltammetry (CV). Depositing MnFe particles onto N–C was shown to significantly enhance electrocatalytic activity for HzOR compared to the Fe/N–C catalyst and especially to the MnFe particles catalyst in terms of highly developed porous structure, which offers the largest surface area, lowest onset potential, and highest current density response, resulting in the strongest catalytic activity. These results suggest that the MnFe/N–C catalyst could be a highly promising anode material for HzOR in direct hydrazine fuel cells (DHFCs).