Carbon Dioxide Electroreduction into Syngas Boosted by a Partially Delocalized Charge in Molybdenum Sulfide Selenide Alloy Monolayers. Issue 31 (29th June 2017)

• Record Type: Journal Article
• Authors: Xu, Jiaqi; Li, Xiaodong; Liu, Wei; Sun, Yongfu; Ju, Zhengyu; Yao, Tao; Wang, Chengming; Ju, Huanxin; Zhu, Junfa; Wei, Shiqiang; Xie, Yi
• Is Part Of: Angewandte Chemie international edition. Volume 56:Issue 31(2017)
• Page Start: 9121
• Page End: 9125
• Publication Date: 2017-06-29
• Subjects: alloy monolayers -- carbon dioxide -- electrocatalysis -- reduction -- syngas; Chemistry -- Periodicals; 540
• DOI: 10.1002/anie.201704928
• Languages: English
• ISSNs: 1433-7851

Abstract

Abstract: Structural parameters of ternary transition‐metal dichalcogenide (TMD) alloy usually obey Vegard law well, while interestingly it often exhibits boosted electrocatalytic performances relative to its two pristine binary TMDs. To unveil the underlying reasons, we propose an ideal model of ternary TMDs alloy monolayer. As a prototype, MoSeS alloy monolayers are successfully synthesized, in which X‐ray absorption fine structure spectroscopy manifests their shortened Mo−S and lengthened Mo−Se bonds, helping to tailor the d‐band electronic structure of Mo atoms. Density functional theory calculations illustrate an increased density of states near their conduction band edge, which ensures faster electron transfer confirmed by their lower work function and smaller charge‐transfer resistance. Energy calculations show the off‐center charge around Mo atoms not only benefits for stabilizing COOH* intermediate confirmed by its most negative formation energy, but also facilitates the rate‐limiting CO desorption step verified by CO temperature programmed desorption and electro‐stripping tests. As a result, MoSeS alloy monolayers attain the highest 45.2 % Faradaic efficiency for CO production, much larger than that of MoS2 monolayers (16.6 %) and MoSe2 monolayers (30.5 %) at −1.15 V vs. RHE. This work discloses how the partially delocalized charge in ternary TMDs alloys accelerates electrocatalytic performances at atomic level, opening new horizons for manipulating CO2 electroreduction properties. Abstract : CO2 conversion : MoSeS alloy monolayers have been synthesized by a liquid–liquid interface‐mediated strategy, in which X‐ray absorption fine structure spectroscopy manifested shortened Mo−S and lengthened Mo−Se bonds. Calculations show that the off‐center charge around Mo atoms not only stabilizes the COOH* intermediate, but also facilitates the rate‐limiting CO desorption step.