Intrinsic Electron Localization of Metastable MoS₂ Boosts Electrocatalytic Nitrogen Reduction to Ammonia

Abstract

The advancement of efficient electrocatalysts toward the nitrogen reduction reaction (NRR) is critical in sustainable ammonia synthesis under ambient pressure and temperature. Manipulating the electronic configuration of electrocatalysts is particularly vital to form metal–nitrogen (MN) bonds during the NRR through regulating the active electronic states of sites. Here, in sharp contrast to stable 2H MoS2 without metal chains, MoMo bonding in metastable polymorphs of MoS2 bulk (zigzag chain in the 1T′ phase and diamond chain in the 1T″′ phase) is discovered to significantly increase intrinsic electron localization around the metal chains. This can enhance the charge transfer from the adsorbed nitrogen molecule to the metal chains, allowing for boosted NRR kinetics. The electrochemical experiments show that the NH3 yield rate and the faradaic efficiency of the metastable 1T″′ MoS2 rich with abundant Mo–Mo bonds are about 9 and 12 times above average than those of 2H MoS2, correspondingly. Theoretical simulations reveal the high local electron density surrounding the MoMo chains and sites can promote π back‐donation, which is beneficial for increasing nitrogen adsorption, strengthening the MN bonds, and reducing the cleavage barrier of the triple NN bond.

Lattice‐Confined Single‐Atom Fe1Sx on Mesoporous TiO2 for Boosting Ambient Electrocatalytic N2 Reduction Reaction

“…To ensure the reliability of the NRR performance, ion chromatography (IC) was employed to quantify NH 3 production at −0.15 V–−0.35 V and the result was almost consistent with that of the IB method (Figure S11) [14] . Notably, the activity of this catalyst can rival most of the reported catalysts (Table S1), such as MoS 2 ‐Fe, Co‐MoS 2 , Zr‐TiO 2 , etc [15, 16, 37–52] . The yield of possible byproduct N 2 H 4 was detected by the Watt and Chrisp method [53] .…”

Metal‐Free Boron/Phosphorus Co‐Doped Nanoporous Carbon for Highly Efficient Benzyl Alcohol Oxidation

“…The electronic localization in these active sites would be weaker than that in BPO but higher than that in C 3 PO, as the electronegativity of B is lower than that of C and P. The B dopant significantly enhances the local electron density of BPC, which is conducive to the movement of valence electrons in the active sites and increases the rate of the catalytic oxidation reaction. [ 36 , 37 ] Owing to the electron‐withdrawing ability of the electronegative N atom, the connected C atoms donate electrons in NPC, enhancing the positive charges of the C atoms and decreasing the localization strength of the valence electrons in the P—N and N—C bonds. This may not be beneficial for generating additional active sites with a certain negative effect on redox reactions.…”

Activation of MoS2 monolayer electrocatalysts via reduction and phase control in molten sodium for selective hydrogenation of nitrogen to ammonia

“…The molten-Na-assisted intercalation and subsequent chemical conversion and its effect on MoS x phase were further verified by X-ray diffraction (XRD) analysis. Figure 2a These downshifts of 1T phase are attributable to the change of Fermi-level induced by electron filling in the Mo d orbitals [32][33][34] . Remarkably, the signals from 1T phase (green areas) gradually dominant the main composition with increase the reaction time from 0 to 30 min, which comfirm that the molten-Na-assisted process effectively transformed 2H to 1T.…”