Lattice‐Confined Pt‐Ru Dual‐Atom Pair by Space Guard for Robust Hydrogen Evolution with Reversible Hydrogen Spillover

Abstract Tuning the chemical microenvironment of dual‐atom catalysts is a significant challenge in boosting electrocatalytic hydrogen evolution reaction (HER). Here, a “space guarding” strategy is proposed to precisely place Pt‐Ru dual‐atom pair sites confined in W 2 N lattice using polyoxometalates (POMs) K 10 [Zn 4 (H 2 O) 2 (PW 9 O 34 ) 2 ] as a rigid template. The pre‐reserved localized defects capture Pt‐Ru pair site and provide the specific W‐Pt‐N‐Ru coordination environment. The obtained PtRu@W 2 N DF @NC catalyst exhibits superior performance with an unprecedented mass activity of 72.7 A mg (Pt+Ru) −1 in 0.5 M H 2 SO 4 and stable electrochemical HER performance for 1200 h. With insights from in‐situ Raman spectroscopy and theoretical calculations, the overall hydrogen evolution pathway proceeds along three steps: fast H 2 O adsorption on W site, facile H* and OH* respective migration from W site to Pt and Ru sites via its distinct electronic flows, and favorable H 2 desorption on Pt site. This work demonstrates a dual‐atom placing strategy via precise lattice‐confinement for the construction of high‐performance HER electrocatalysts.