Enhanced-electrocatalytic activity of Ni1−xFex alloy supported on polyethyleneimine functionalized MoS2 nanosheets for hydrazine oxidation

Abstract

A high-performance Ni_1−xFe_x on polyethyleneimine (PEI)-functionalized molybdenum disulfide (MoS₂) electrocatalyst has been synthesized by an electroplating in situ growth approach. Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy confirm the successful functionalization of MoS₂ with PEI. The empty orbitals of Ni²⁺ and Fe²⁺ (Ni and Fe precursors) coordinated with the donated lone pairs of nitrogen atoms in PEI-mediated MoS₂ and then the Ni²⁺ and Fe²⁺ were in situ reduced at a negative potential. Transmission electron microscope images and X-ray diffraction reveal that Ni₈₅Fe₁₅ nanoparticles with an average size of 2.25 nm are uniformly dispersed on the PEI–MoS₂ sheets. The Ni_1−xFe_x/PEI–MoS₂ catalyst exhibits unexpectedly high activity towards the hydrazine oxidation reaction, which can be attributed to highly homogeneous dispersed Ni_1−xFe_x alloy. It also shows enhanced electrochemical stability due to the structural integrity of PEI–MoS₂. Finally, the Ni₈₅Fe₁₅/PEI–MoS₂ catalyst is proved to be very valuable for applications in hydrazine fuel cells, as compared with Ni₉₀Fe₁₀/PANi–MoS₂ and Ni₈₅Fe₁₅/MoS₂ catalysts.