Facile construction of Mo₂C-MoC heterojunction electrocatalysts for enhanced hydrogen evolution reaction

Electrocatalytic decomposition of water represents a viable route for green hydrogen generation, where molybdenum carbide (Mo₂C) serves as a highly active catalytic material toward the cathodic proton reduction process. In this work, a Mo₂C-MoC/NC composite was synthesized via dicyandiamide dosage modulation and high-temperature calcination, with a detailed examination of the influence that dicyandiamide loading exerts upon its architecture and catalytic activity. Results show that the optimized Mo₂C-MoC/NC-0.3 catalyst possesses a loose, porous architecture, which markedly raising both active site population plus accessible interfacial region. Meanwhile, Mo²⁺ along with Mo³⁺ species adjust the electron configuration within this material while decreasing H binding strength, consequently greatly improving HER performance. Within a 1 molar KOH medium, this material demands merely 87 mV to reach 10 mA cm⁻², alongside a Tafel indicator equaling 54.80 mV dec⁻¹, and maintains stable performance over 100 h, demonstrating outstanding catalytic activity and durability. Our findings provide guidance for tuning the phase structure of Mo-based carbides to improve HER performance.