A multifunctional Mo–N/Fe–N interfaced MoS2/FeNC electrocatalyst for energy conversion applications

Abstract

Heteroatom doping and phase engineering have become captivating strategies to boost the multifunctional catalytic activity of an electrocatalyst for energy conversion. In this study, for the first time, we synthesized a polymer–iron complex (Fe-polydiaminonaphthalene) and pyrolyzed it to produce Fe and N doped carbon nanospheres, and then vertically aligned MoS₂ nanosheets were anchored to the doped carbon nanospheres (MoS₂/FeNC). During pyrolysis, Mo–N was formed in the MoS₂/FeNC matrix and served as an active site enabling robust trifunctional catalytic activity towards the ORR, the HER, and H₂O₂ reduction. MoS₂/FeNC exhibits excellent performance for the ORR with onset and half-wave potentials (E_1/2) of 0.988 V and 0.866 V (vs. RHE), respectively, and a Tafel slope of 58 mV dec⁻¹, better than those of benchmark Pt/C (E_1/2 = 0.861 V and 60 mV dec⁻¹), with excellent methanol tolerance and stability in 0.1 M KOH. The catalytic activity towards the HER is also remarkable, with an overpotential of 128 mV at 10 mA cm⁻² in alkaline media. Additionally, the electrocatalytic behavior towards H₂O₂ reduction exhibits enhanced analytical performance for detecting H₂O₂ from A549 cells with a low detection limit of 200 nM (S/N = 3). The energy level and charge distribution calculation for the proposed catalysts suggested that forming MoS₂ nanosheets on the FeNC surface facilitated multifunctional catalytic activity for sustainable applications.