Cobalt-Modulated Molybdenum–Dinitrogen Interaction in MoS₂ for Catalyzing Ammonia Synthesis

Abstract

Dinitrogen conversion to ammonia via electrochemical reduction with over 10% Faradaic efficiency is demonstrated in this work. Co-doped MoS 2-x polycrystalline nanosheets with S vacancies as the catalysts are loaded onto carbon cloth by hydrothermal growth from Mo, Co, and S precursors. A sulfur vacancy on the MoS 2-x basal plane mimicking the natural Mo-nitrogenase active site is modified by Co doping and exhibits superior dinitrogen-to-ammonia conversion activity. Density-functional simulation reveals that the free energy barrier, which can be compensated by applied overpotential, is reduced from 1.62 to 0.59 eV after Co doping. Meanwhile, dinitrogen tends to be chemically adsorbed to defective MoS 2-x , which effectively activates the dinitrogen molecule for the dissociation of the NN triple bond. This process is further accelerated by Co doping, resulting from the modulation of Mo−N bonding configuration.

Recent advances in single metal atom-doped MoS2 as catalysts for hydrogen evolution reaction

“…The loading amount of Pt was about 1.7 wt% measured by ICP-OES. For SA-Co doped MoS 2 , it was prepared by using the same Mo precursor, but with CH 4 N 2 S as the S source and Co(NO 3 ) 2 •6H 2 O as the Co source [49]. A uniform distribution of Co over the MoS 2−x lattice was observed from the energy-dispersive X-ray spectroscopy (EDS) mapping (Fig.…”

General Synthesis of Nanoporous 2D Metal Compounds with 3D Bicontinous Structure

“…The nanoporous structure, Se-vacancy with highly exposed surfaces, and abundant 1T phase transition-metal dichalcogenides mean that they could be directly used as electrocatalysts for the N 2 reduction reaction (NRR, See Supplementary methods). [50][51][52] Linear-sweep-voltammetry (LSV) measurements were performed under N 2 -and Ar-saturated Na 2 SO 4 solutions to confirm the electrochemical onset potential of the NRR ( Figure S22 cat. at −0.3 V versus RHE ( Figures S23-S25, Supporting Information), respectively, which are comparable to most of the catalysts in aqueous electrolytes under ambient conditions (Table S5, Supporting Information).…”

“…The nanoporous structure, Se‐vacancy with highly exposed surfaces, and abundant 1T phase transition‐metal dichalcogenides mean that they could be directly used as electrocatalysts for the N 2 reduction reaction (NRR, See Supplementary methods). [ 50–52 ] Linear‐sweep‐voltammetry (LSV) measurements were performed under N 2 ‐ and Ar‐saturated Na 2 SO 4 solutions to confirm the electrochemical onset potential of the NRR (Figure S22, Supporting Information). The LSV curves of np‐MoSSe have the same shape but an increased current density below ‐0.2 V versus reversible hydrogen electrode (RHE) under N 2 atmosphere, indicating that the electroreduction of N 2 to NH 3 is occurring.…”

“…at ‐0.3 V versus RHE (Figures S23–S25, Supporting Information), respectively, which are comparable to most of the catalysts in aqueous electrolytes under ambient conditions (Table S5, Supporting Information). [ 50–52 ] The hydrogen production selectivity was further investigated using the gas chromatography to support the reliability of the NRR FE results at different potentials (Figure. S26, Supporting Information).…”

Exposure of Definite Palladium Facets Boosts Electrocatalytic Nitrogen Fixation at Low Overpotential

“…Therefore, in the long run, this process is not economical and environmentally friendly. [ 8 ] In the past few decades, various alternative approaches have been investigated for ammonia synthesis, including enzymatic reduction methods by nitrogenase enzymes; [ 9 ] photocatalytic methods by bio/inorganic hybrids, [ 10,11 ] biomimetic chalcogels, [ 12 ] and pure inorganic semiconductors; [ 13,14 ] and electrocatalytic methods using noble metals, [ 15–23 ] non‐noble‐metal‐based materials, [ 24–28 ] and nonmetallic materials. [ 29–33 ] Among them, electrochemical reduction of N 2 is favored due to its advantages of the simplicity, sustainability, high energy conversion efficiency, and avoiding the use of costly agents.…”