Cation doping driven performance optimization of MoS₂ nanoarrays for nitrate and sulfide co-electrolysis

Simultaneous nitrate reduction and sulfide oxidation reactions (NO₃RR and SOR) to generate valuable chemicals represent an appealing strategy for green synthesis; however, the sluggish kinetics seriously hinder their application. Herein, we report that Ni dopants can optimize the electronic structure of MoS₂, which thus favors the adsorption of reactants/intermediates and reduces the corresponding energy barriers. As a result, the designed catalyst shows a maximal Faradic efficiency of 88.4% and a corresponding yield rate of 66.7 μmol·h⁻¹·cm⁻² for NH₃ synthesis, accompanied by a high robustness over 60 h. Besides, it can also trigger the SOR activity with a low potential of 0.105 V vs. reversible hydrogen electrode (RHE) to produce 10 mA·cm⁻², far smaller than that needed for conventional water oxidation (1.545 V vs. RHE). Accordingly, a coupling system with NO₃RR and SOR is constructed for synchronous formation of value-added products on both anode and cathode. This work demonstrates an attractive attempt to construct advanced MoS₂-based catalysts towards electrosynthesis.