Multifunctional Monolithic TaS 2 /3D‐Ta Gas Diffusion Layers for Electrochemical Interface Engineering

ABSTRACT Two‐dimensional metallic transition‐metal dichalcogenides provide conductive and catalytically active surfaces, while three‐dimensional porous metal frameworks offer continuous transport pathways and mechanical robustness. Hybridizing these complementary structures into a monolithic architecture is attractive for electrochemical interface engineering, but it remains challenging to integrate their advantages into a single component that coordinates mass transport, interfacial contact, and surface reactivity. Herein, we develop a multifunctional monolithic TaS 2 /3D‐Ta gas diffusion layer (GDL) by 3D printing a porous Ta scaffold followed by a direct sulfurization process to form vertically‐aligned TaS 2 nanosheet networks. The resulting monolith features ordered, thorough pores (∼285.7 µm mean pore size), low interfacial resistances (∼2 mΩ cm 2 at 150 N cm −2 ), and high electrocatalytic hydrogen evolution activity (Tafel slope of ∼55.3 mV dec −1 ), thereby functioning as a high‐porosity transport framework, a contact‐optimized interface, and a catalytically active surface. The designed TaS 2 /3D‐Ta is further demonstrated as an efficient cathodic GDL in a proton‐exchange‐membrane water electrolysis cell, affording a lower working voltage (by ∼0.54 V) at 2 A cm −2 than that of commercial carbon paper GDL. This work hereby provides a monolithic hybridization strategy for constructing multifunctional electrochemical interface materials.