Synergistic Coupling Effects of Co and MoC in Co-MoC Heterostructures for Efficient Electrocatalytic Nitrate...

Electrocatalytic nitrate reduction (NO₃ ^-RR) offers a promising route for ammonia (NH₃) synthesis and wastewater treatment. Yet its multi-step proton-electron transfer and the difficulty in synergistically regulating intermediate adsorption greatly limit reaction efficiency. Herein, we propose a rational strategy to enhance the electrocatalytic performance of MoC via the construction of a cobalt and MoC heterostructure anchored on a nitrogen-doped carbon framework (Co-MoC/NC). Both experimental and theoretical calculations demonstrate that the significant improvements are attributed to the synergistic effects between Co and MoC. Specifically, macroscopic electron transfer proceeds from Co to the MoC phase, leading to decreased localized electron density at the Co sites. This interfacial charge rearrangement effectively optimizes the electronic structure of the catalytic center, lowering the kinetic barrier for the rate-determining step. The as-synthesized Co-MoC/NC catalyst exhibited superior electrocatalytic NO₃ ^-RR performance in an alkaline electrolyte. It achieved a maximum NH₃ yield rate of 67.7 ± 0.7 mg h^-1 mg_cat. ^-1 at -0.6 V (vs. RHE), and a maximum Faradaic efficiency (FE) of 90.6 ± 2.1% at -0.4 V (vs. RHE). This work presents a strategy for regulating heterogeneous structure catalysts, which holds great potential for cost-effective and large-scale ammonia production from wastewater.