Interfacial charge engineering of Pt-Mo2C heterostructures for robust oxygen reduction reaction

Abstract

The commercialization of fuel cells is severely impeded by the sluggish kinetics of oxygen reduction reaction (ORR) and instability of conventional Pt/C catalysts, primarily due to weak metal-support interactions. Here, we propose an interfacial charge engineering strategy to construct robust Pt-Mo 2 C heterostructures on nitrogen-doped carbon. Synthesized via a scalable, in-situ concurrent pyrolysis-reduction, the nanocomposite features precisely modulated electronic coupling. X-ray absorption fine structure spectroscopy confirms strong interfacial interaction, delineated by a distinct Pt-Mo bond (~ 2.72 Å) and a high Pt-Mo coordination number (~ 1.81). Theoretical calculations demonstrate that this heterostructured interface functions as an electronic reservoir, driving directional charge redistribution. This transfer downshifts the d -band center of interfacial Pt atoms, thereby optimizing the binding strength of oxygenated intermediates and accelerating ORR kinetics. Electrocatalytic measurements reveal that the engineered Pt-Mo 2 C/NC catalyst delivers an outstanding mass activity of 0.65 A mg − 1 Pt at 0.9 V, outperforming commercial Pt/C by a factor of 4.8. Moreover, the robust Pt-Mo 2 C coupling effectively suppresses Pt dissolution and agglomeration, endowing the catalyst with exceptional durability, retaining ~ 90% of its mass activity after 20,000 potential cycles. These results offer a general design principle for active, durable electrocatalysts based on targeted interfacial electronic modulation.