Second‐Scale Flame Synthesis of Pt Nanocluster Continuum for Efficient Hydrogen Evolution

ABSTRACT Maximizing Pt utilization while maintaining high activity and durability is crucial for practical hydrogen evolution reaction electrocatalysts, yet conventional Pt/C suffers from tortuous electron pathways and particle coarsening. Here we report a second‐scale, furnace‐free flame synthesis that constructs a Pt nanocluster continuum (Pt‐NCC) on N‐doped carbon‐coated nickel foam under ambient conditions. By tuning the Pt precursor concentration, Pt species are transformed from isolated single atoms to nanoclusters and finally to a conformal percolated continuum of tightly fused ∼2 nm domains. A transient high‐temperature window enforces diffusion‐controlled growth while suppressing Ostwald ripening, freezing a continuous Pt nanocluster framework. Pt‐NCC integrates uninterrupted Pt‐Pt pathways with a reduced Pt‐C interfacial area, yielding ultralow charge‐transfer resistance and enlarged electrochemically accessible surface area. In 1 M KOH, Pt‐NCC requires only 83.6 mV to reach 300 mA cm −2 and maintains excellent durability for over 200 h at 100 mA cm −2 . This flame strategy offers a general route to percolated noble‐metal networks for high‐efficiency electrochemical energy conversion.