Ultralow-Concentration Pt-Decorated Carbon Sphere Catalyst for Enhanced Hydrogen Evolution Reaction.

Ultralow decoration of platinum nanoparticles (Pt NPs) (0.32 wt %) onto carbon spheres (CS) has been developed for hybrid formation, using hydrothermal heat treatment, followed by chemical reduction of nanoparticles. The successful decoration of CSs bearing amine groups with platinum nanoparticles was confirmed directly by X-ray photoelectron spectroscopy. The uniform distribution and crystallinity of the Pt NPs in the hybrid structures were confirmed from X-ray diffraction spectroscopy and transmission electron microscopy. The hydrogen evolution reaction studied on the proposed Pt-CS hybrids reveals an onset potential of only -144 mV (vs RHE, reversible hydrogen electrode) with a current density of 10 mA/cm² under an acidic 0.5 M H₂SO₄ medium, which exhibits a better performance as compared to a similar Pt-carbon hybrid catalyst reported in the literature. The Pt-CS hybrid stability assessments revealed a minimal overpotential loss (9 mV) from 144 to 153 mV after 200 cycles. Such hybrids have possible applications in environmental water purification and renewable energy production.