MOF-derived Fe2O3@MoS2: An efficient electrocatalyst for ammonia synthesis under mild conditions

Electrochemical ammonia synthesis (EAS) is considered to be an ecofriendly and sustainable method for artificial N 2 fixation. It is urgent to develop cost-effective and efficient electrocatalysts for EAS because present catalysts have low activity and poor selectivity. Herein, Fe 2 O 3 nanoparticles anchored on MoS 2 nanoflowers (Fe 2 O 3 @MoS 2 ) were developed as a highly efficient EAS electrocatalyst under ambient conditions. Electrochemical measurements indicate that Fe 2 O 3 @MoS 2 achieves a remarkable NH 3 yield of 112.15 μg h −1 mg cat −1 at − 0.6 V vs. reversible hydrogen electrode (RHE) and a high faradaic efficiency (FE) of 8.62% at − 0.4 V vs. RHE in 0.1 M Na 2 SO 4 , much better than the EAS performance of separate MoS 2 and Fe 2 O 3 . The superior electrochemical stability is confirmed by long-term (at least 24 h) continuous tests. Density functional theory (DFT) calculations show that Fe 2 O 3 @MoS 2 , compared to MoS 2 , is better able to activate inert N 2 molecules, as reflected by its greater adsorption energy (−0.32 eV vs. − 0.10 eV), greater N≡N bond distance (1.223 Å vs. 1.159 Å), lower energy barrier (0.40 eV vs. 0.78 eV), and greater charge transfer from active sites to N 2 molecules (1.16 e − vs. 0.62 e − ). Thus, this work provides new perspectives on the development of efficient EAS catalysts using MoS 2 -based materials as the substrate.