Ion‐Assisted Preparation of Bimetallic Porous Nanodendrites for Active and Stable Water Electrolysis

Abstract Delicate electrochemical active surface area (ECSA) engineering over the exposed catalytic interface and surface topology of platinum‐based nanomaterial represents an effective pathway to boost its catalytic properties toward the clean energy conversion system. Here, for the first time, the facial and universal production of dendritic Pt‐based nanoalloys (Pt‐Ni, Co, Fe) with highly porous feature via a novel Zn²⁺‐mediated solution approach is demonstrated. In the presence of Zn²⁺ during synthesis, the competition of different galvanic replacement reactions and consequently generated “branch‐to‐branch” growth mode are believed to play key roles for the in situ fabrication of such unique nanostructure. Due to the fully exposed active sites and ligand effect‐induced electronic optimization, electrochemical hydrogen evolution in alkaline media on these catalysts exhibit dramatic activity enhancement, delivering a current density of 30.6 mA cm⁻² at a 70 mV overpotential for the Pt₃Ni nanodendrites and over 7.4 times higher than that of commercial Pt/C. This work highlights a general and powerful ion‐assisted strategy for exploiting dendritic Pt‐based nanostructures with efficient activities for water electrolysis.