Electrocatalytic Reduction of N₂ to NH₃ Over Defective 1T′‐WX₂ (X=S, Se, Te) Monolayers

Abstract

Defects in transition metal dichalcogenides (TMDs) can serve as active sites in catalytic reactions. In this work, by means of first‐principles calculations, the catalytic activities of WX2 (X=S, Se, Te) monolayers in the 1T′ phase with both vacancy defects (missing chalcogen atoms, XVd) and antisite defects (replacing chalcogen atoms with W atoms, XAd) were evaluated for the nitrogen reduction reaction (NRR). Results showed that all these defective catalysts had great potential toward electrocatalytic ammonia synthesis by exhibiting low limiting potentials (UL). Over 1T′‐WTe2@TeVd, 1T′‐WS2@SAd, 1T′‐WSe2@SeAd, and 1T′‐WTe2@TeAd, the corresponding UL values were −0.49, −0.21, −0.19, and −0.15 V, much smaller than that of the benchmark catalyst, the Ru (0001) surface (UL=−0.98 V). Furthermore, the hydrogen evolution reaction (HER) was inhibited. 1T′‐WX2 monolayers with the antisite defects showed better NRR activity than those with the vacancy defects because of the smaller steric hindrance at the former. Results suggest that the steric effect at the active surface sites should be utilized to develop better catalysts.

Design of Electrocatalytic Janus WSeS/WSe2 Heterostructure Nanowall Electrodes with High Selectivity and Faradaic Efficiency for Nitrogen Reduction

“…This comprehensive analysis involved chronoamperometry measurements (CA) under N 2 bubbling, with precise control of experimental conditions facilitated by a mass flow controller (MFC). Various applied po-tentials were tested, and accurate measurements were obtained through the use of colorimetric analysis, and quantitative nuclear magnetic resonance (qNMR).. [56][57][58] After the CA test of Janus WSeS/WSe 2 heterostructure nanowalls at applied potentials in the range of −0.7 to −0.2 V versus RHE for 2 h, the resulting electrolytes were collected to determine the NH 3 concentrations using the indophenol blue (IPB) method, as shown in Figure 3d, Figure S11a,c (Supporting Information). As a result, the maximum yield rate (13.97 μg h-mg cat −1 ) and Faradaic efficiency (FE) (35.24%) were achieved at the applied potential of −0.3 V (vs RHE).…”

Unlocking the potential of alkaline-earth metal active centers for nitrogen activation and ammonia synthesis: the role of s–d orbital synergy

“…Additionally, the COHP analysis in Fig. S4 † demonstrates partial lling of the 2p* antibonding orbitals of *N 2 and the ICOHP of *N 2 (−17.07 eV) being less negative than that of the free N 2 molecule (−22.98 eV), 54 further suggesting the potent ability of Ca 2 @WS 2 to activate the N 2 molecule.…”

Phase Engineering of Nanomaterials: Transition Metal Dichalcogenides

“…Electrocatalytic nitrogen reduction (NRR) has demonstrated great potential to replace the energy-intensive Haber–Bosch process for synthesizing NH 3 from N 2 . Metastable TMDs have demonstrated superior catalytic activities in NRR. − For instance, Lin et al prepared 2H-, 1T′-, and 1T‴-MoS 2 as NRR electrocatalysts to investigate the role of the crystal phases of TMDs on the performance of NRR. The 1T‴-MoS 2 achieved the highest NH 3 yield rate of 9.09 μg h –1 mg –1 at −0.3 V vs. RHE (Figure a), which was much higher than those (Figure b) of the 1T′-MoS 2 and 2H-MoS 2 .…”