Constructing N- and F-Dual-Doped Pt-Based Heterojunction Catalysts via Synergistic Electronic Modulation for Enhanced Hydrogen Evolution Reaction Activity and CO Tolerance

The development of efficient and durable hydrogen evolution reaction (HER) electrocatalysts is critical for sustainable energy conversion. Although platinum (Pt) serves as a benchmark HER catalyst, its practical application is hindered by the high cost, limited durability, and susceptibility to CO poisoning. In this work, we report a heterojunction Pt-based catalyst, Pt@NCL-MXene, synthesized by LiF etching of MXene and subsequent NH₃ calcination. This process introduces dual nitrogen (N) and fluorine (F) doping and yields a nitrogen-doped carbon layer (NCL) coating on Pt nanoparticles with an average size of only 3.4 nm. Compared with conventional Pt–C catalysts, Pt@NCL-MXene exhibits a larger specific surface area, enhanced electron transfer efficiency, and an optimized d-band center, thereby facilitating both H* adsorption and desorption. As a result, Pt@NCL-MXene achieves a significantly lower overpotential of 73 mV at a current density of 100 mA cm^–2, alongside improved kinetics and stability under operational conditions. Furthermore, the 9 wt % F-rich MXene support effectively suppresses CO adsorption on Pt, reducing the CO uptake to 0.224 mmol g^–1, which is purportedly lower than that of Pt–C (0.264 mmol g^–1), thereby mitigating CO poisoning and prolonging the catalyst’s service life. These findings offer insights into the rational design of advanced CO-resistant Pt-based HER electrocatalysts.