Atomic‐Layered Platinum‐Based Intermetallic with Phosphorus Pillar Nanoengineering Enables pH‐Universal Hydrogen Oxidation Catalysis

Abstract Layered materials boost hydrogen energy catalytic efficiency by expanding electrochemically surface area and elevating the intrinsic site activity. However, synthesizing atomically layered platinum intermetallic catalysts remains challenging due to platinum’s bulk crystallization tendency. Herein, we first prepare Pt 5 GaP and Pt 5 InP nanoparticles with self‐supported interlayer tunnels via pillar nanoengineering, featuring Pt 5 X (X = Ga/In) tri‐layers alternating with “P pillars”. The pillar effect enables selective H 2 transport while blocking CO, endowing superior full‐pH HOR activity and CO tolerance vs. commercial Pt/C. Pt 5 InP exhibits 13.9‐ and 11.5‐fold higher mass activity than Pt/C at pH = 1 and 13 (50 mV overpotential) with exceptional CO resistance. This novel layered compound and generalizable strategy pave the way for atomic‐scale platinum‐based catalysts, offering a tunnel size‐dependent CO‐tolerant approach and expanding small‐molecule catalysis applicability.