Mutual promotion by structural design and intrinsic activity coupling of CNTs/MoC/CoNiMo for water splitting and urea electrolysis

Abstract

Construction of durable multi-function electrocatalysts for hydrogen production is still highly challenging. Herein, we report a hierarchical integrated tri-functional heterogeneous CNTs/MoC/CoNiMo electrode for HER and related OER/UOR. The carbon-protected Ni nanoparticles yield abundant γ-NiOOH active intermediates to boost OER/UOR, while DFT calculations verify Mo migration induced by MoC and CoNiMo alloy under negative potentials generates HER super-active sites on Mo-rich surfaces. Additionally, the parallel aligned nanosheets with out-plane extended CNTs arrays can guide the rapid bubbles release and expand the accessible surface area. Therefore, the optimized CNT/MoC/NMC-3 electrode can achieve overpotentials of 51 mV (HER) and 226 mV (OER), with low potential threshold of 1.257 V (UOR) at 10 mA cm–2. Moreover, the assembled symmetric urea electrolyzer reaches a 1.291 V cell voltage at 10 mA cm–2. This work provides a novel strategy for heterostructure multi-component integration for achieving high-efficiency hydrogen production and urea-containing wastewater purification.