Ultradense ZrC Nanoislands Decorated with Pt Single Atoms for Superior Activity and Durability in Water Electrolysis

Enhancing the stability of Pt single atoms (SAs) remains a critical bottleneck for practical applications. Herein, we overcome this limitation by developing a ZrCl₃-CH₄ system that enables an explosive nucleation to directly construct defect-rich ZrC nanoislands (NIs) on carbon cloth as ultrastable anchoring platforms for Pt single atoms (Pt₁@ZrC NIs). This strategy dramatically enhances the surface number density of ZrC particles by 2 orders of magnitude over conventional methods and eliminates the long-standing issue of free carbon contamination. The Pt₁@ZrC NI electrode exhibits a strong synergy, where ZrC promotes water adsorption/dissociation and Pt facilitates hydrogen migration/desorption, yielding a mass activity 116- and 132-fold greater than that of the commercial Pt@C catalyst in alkaline and acidic media, respectively. Moreover, owing to the excellent acid- and base-resistance of ZrC and its strong binding to Pt SAs and the substrate, the Pt₁@ZrC NIs catalyst maintains exceptional stability in both acidic and alkaline media.