Heterostructured CoS<sub>2</sub>/MoS<sub>2</sub> with a Rich Active Site for an Efficient Electrochemical Nitrate Reduction Reaction to Ammonia
Zixuan Tan, Feng Du, Mengqi Tong, Jundie Hu, Ning Zhang, Shunyuan Huang, Chunxian Guo
Abstract
The electrochemical nitrate reduction reaction (NO 3 – RR) has an important application value in realizing efficient synthesis of ammonia (NH 3 ) from NO 3 –, and obtaining a high-performance and low-cost electrocatalyst is the key. Nonetheless, a majority of the existing catalysts for the NO 3 – RR have the problem of an unsatisfactory NH 3 yield and insufficient stability. Herein, a heterostructured CoS 2 /MoS 2 electrocatalyst is designed and fabricated, and the structure–activity relationship is studied. In comparison to pure CoS 2 and MoS 2, CoS 2 /MoS 2 demonstrates an enhanced performance with 2.8 and 2.0 times the current enhancement, respectively, at an applied potential of −0.25 V versus reversible hydrogen electrode. It is found that the electronic structure of CoS 2 /MoS 2 is modified through electron transfer between Co and Mo for enhanced reaction dynamics. Moreover, in heterostructured CoS 2 /MoS 2, the two components (CoS 2 and MoS 2 ) cooperate well with each other to tailor reaction steps of the NO 3 – RR. Eventually, CoS 2 /MoS 2 achieves a faradaic efficiency of 97.07%, NH 3 yield rate of 0.44 mmol h –1 cm –2, NO 3 – conversion rate of 75.43%, and NH 3 selectivity of 95.45% in a 1.0 M KOH electrolyte with 600 ppm of NO 3 – -N, retaining its promising applications in the NO 3 – RR.