Large‐Scale Synthesis of Multifunctional Single‐Phase Co₂C Nanomaterials

Abstract Achieving scalable synthesis of nanoscale transition‐metal carbides (TMCs), regarded as substitutes for platinum‐group noble metals, remains an ongoing challenge. Herein, a 100‐g scale synthesis of single‐phased cobalt carbide (Co₂C) through carburization of Co‐based Prussian Blue Analog (Co‐PBA) is reported in CO₂/H₂ atmosphere under mild conditions (230 °C, ambient pressure). Textural property investigations indicate a successful preparation of orthorhombic‐phased Co₂C nanomaterials with Pt‐group–like electronic properties. As a demonstration, Co₂C achieves landmark photo‐assisted thermal catalytic CO₂ conversion rates with photo‐switched product selectivity, which far exceeds the representative Pt‐group‐metal–based catalysts. This impressive result is attributed to the excellent activation of reactants, colorific light absorption, and photo‐to‐thermal conversion capacities. In addition to CO₂ hydrogenation, the versatile Co₂C materials show huge prospects in antibacterial therapy, interfacial water evaporation, electrochemical hydrogen evolution reaction, and battery technologies. This study paves the way toward unlocking the potential of multi‐functional Co₂C nanomaterials.