Pt Single Atoms and Clusters Supported on N-Doped Porous Carbon for Improved Hydrogen Evolution Reaction

Platinum is renowned for its exceptional catalytic performance in the hydrogen evolution reaction (HER), but its high cost and rarity seriously hinder the large-scale application of platinum electrocatalysts. Constructing highly dispersed platinum active sites is an effective strategy to lower the loading of Pt while maintaining high activity. Herein, a highly dispersed Pt catalyst composed of a mixture of single atoms and clusters is synthesized on porous N-doped carbon (Pt/N-PC) derived from renewable peony. The existence of Pt single atoms and clusters was confirmed by combining methods such as aberration-corrected high-angle annular dark field-scanning transmission electron microscopy images (HAADF-STEM), X-ray absorption fine structure (XAFS), and X-ray photoelectron spectroscopy (XPS). The Pt/N-PC catalyst exhibits superior performance compared to the Pt-free catalyst (N-PC) as well as to the commercial 20 wt % Pt/C catalyst. It exhibits an overpotential of just 11 mV at a current density of 10 mA/cm², a Tafel slope of 24.1 mV/dec, and an exceptional long-term durability in acidic environments. Notably, upon optimizing the geometric loading amount of Pt, the optimal catalyst achieves an ultrahigh platinum mass activity of 3.44 A mg^–1_Pt at a potential of −50 mV. This value is approximately 9.5 times greater than that of the commercial 20 wt % Pt/C catalyst (0.36 A mg^–1_Pt).