Synergistic interaction of monodisperse Pt nanoparticles with defect-rich graphene aerogel for efficient acidic hydrogen evolution

Solving the problem of aggregation and nonuniform dispersion of platinum (Pt) nanoparticles (NPs) is the key to obtaining high catalytic activity. Graphene aerogels (GAs) with large accessible specific surface area and abundant surface defects are considered to be excellent substrate materials for reducing Pt agglomeration and enhancing catalytic activity. Herein, Pt-based GA composites (Pt-GA-x) featuring homogeneous particle dispersion and high activity were successfully synthesized through a one-step reduction method. Fourier transform infrared (FTIR), Raman, and X-ray photoelectron spectroscopy (XPS) test results indicate that the presence of a large number of oxygen-containing functionalities in GA for anchoring Pt NPs, and the interaction with GA produces electronically structured Pt and defect-rich GA substrates. The obtained electrocatalyst Pt-GA-2 possesses a large specific surface area (443.46 m²·g⁻¹), low Pt loading (3.08 wt%), and uniformly dispersed Pt NPs (average 42 nm). As an advanced hydrogen evolution reaction (HER) electrocatalyst, an overpotential of 34 mV is achieved at a current density of 10 mA·cm⁻² in 0.5 M H₂SO₄ electrolyte, together with a low Tafel slope of 33.2 mV·dec⁻¹. Hence, high mass activity (5623 mA·mg_Pt⁻¹) and turnover frequency (TOF = 2.57 s⁻¹ at η = 100 mV) can be obtained, which are 6.81 and 6.76 times higher than those of commercial Pt/C catalysts. All these are attributed to enormous surface defects over GA and electron enrichment on Pt NPs. The present study highlights the unique advantages of GA in electrochemical energy conversion and provides new avenues to fabricate advanced HER electrocatalysts.

Graphical abstract