Printed Liquid Metal-Solid Metal Hybrid Electrodes for Stabilizing Liquid Platinum-Gallium Droplets During Electrocatalysis.

Abstract

Dispersing catalytically active gallium (Ga)-based liquid metal (LM) nano- and micro-droplets onto solid metallic mesh substrates remains challenging due to their strong tendency to either agglomerate or migrate away from the substrate. Another challenge is the reactivity of Ga with support metals, often forming discrete solid intermetallic phases. Here, we develop a 3D matrix formed by fused tungsten nanoparticles (W NPs) to physically entrap Ga-based LM nano-droplets, which effectively prevent their agglomeration and stabilize their reactive surface. Printing these W/LM composites onto a porous substrate (e.g., molybdenum (Mo) mesh) further promoted their dispersion and brought about enhanced electrochemical reactivity. To verify the efficiency of this strategy, we printed Pt-in-Ga droplets mixed with W NPs onto porous Mo substrate and evaluated their performance by two model reactions-CO₂RR (CO₂ reduction reaction) and HER (Hydrogen evolution reaction). The printed showed remarkable stability and reactivity toward both reactions. In addition, computational investigations revealed distinct active motifs for these two reactions, supporting the notion that adaptive LM catalysts can facilitate diverse reaction pathways depending on the targeted reactions.