Heterostructured CoS₂/MoS₂ with a Rich Active Site for an Efficient Electrochemical Nitrate Reduction Reaction to Ammonia

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 highperformance 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.

Recent Progress and Perspectives on Transition Metal-Based Electrocatalysts for Efficient Nitrate Reduction

“…The electrochemical activity of the Ni foam electrode was significantly improved by the introduction of Co. The CoS 2 /MoS 2 heterostructure studied by Tan et al demonstrated that bimetallic interactions and electron transfer facilitated the reaction process. Excellent performance (97.07% FE and 95.45% NH 3 selectivity) was obtained for their electrocatalyst.…”

2023 Pioneers in Energy Research: Shizhang Qiao

“…Ammonia is another decarbonized energy vector (like H 2 ), which can be produced by electrocatalytic conversion of N 2 . Tan et al proposed a heterostructured CoS 2 /MoS 2 catalyst for the synthesis of ammonia by the electrochemical nitrate reduction reaction. This heterostructure tailored reaction steps of the nitrate reduction and increased the NH 3 yield.…”