Oxygen-doped MoS₂ nanoflowers with sulfur vacancies as electrocatalyst for efficient hydrazine oxidation

Direct hydrazine fuel cells (DHFCs) fuel has drawn significant attention due to its characteristics of high energy density. Substantial effort is still needed to explore sustainable and efficient catalysts for hydrazine oxidation reaction (HzOR). Herein, inspired by reducing solvents that can protect the precursors of nanomaterials from oxidation, oxygen-doped MoS2 nanoflowers with sulfur vacancies (O-rich MoS2) were prepared via a simple synthesis method using the readily available ethanol/water as the solvent and applied as electrocatalyst for HzOR. It is found that the ratio of ethanol to water has a significant influence on the morphology of MoS2 and the catalytic performance of hydrazine oxidation. Moreover, the concept of O-doping is proposed by introducing oxygen atoms to mostly replace bulk S atoms in the oxidation process of nanomaterials. The sulfur vacancy and doping were regarded as the main active site for the HzOR. Accordingly, the onset potential of the prepared electrocatalyst is 0.5 V vs. RHE in a 1 M KOH/0.1 M hydrazine electrolyte. This doping method can provide new ideas for improving the construction of hydrazine oxidation catalysts in the future.