A durable and pH-universal self-standing MoC–Mo2C heterojunction electrode for efficient hydrogen evolution reaction
Wei Liu, Xiting Wang, Fan Wang, Kaifa Du, Zhaofu Zhang, Yuzheng Guo, Huayi Yin, Dihua Wang
Abstract
Abstract Efficient water electrolyzers are constrained by the lack of low-cost and earth-abundant hydrogen evolution reaction (HER) catalysts that can operate at industry-level conditions and be prepared with a facile process. Here we report a self-standing MoC–Mo 2 C catalytic electrode prepared via a one-step electro-carbiding approach using CO 2 as the feedstock. The outstanding HER performances of the MoC–Mo 2 C electrode with low overpotentials at 500 mA cm −2 in both acidic (256 mV) and alkaline electrolytes (292 mV), long-lasting lifetime of over 2400 h (100 d), and high-temperature performance (70 o C) are due to the self-standing hydrophilic porous surface, intrinsic mechanical strength and self-grown MoC (001)–Mo 2 C (101) heterojunctions that have a Δ G H* value of −0.13 eV in acidic condition, and the energy barrier of 1.15 eV for water dissociation in alkaline solution. The preparation of a large electrode (3 cm × 11.5 cm) demonstrates the possibility of scaling up this process to prepare various carbide electrodes with rationally designed structures, tunable compositions, and favorable properties.