Visualizing Formation of Tungsten Carbide Model Catalyst and its Interaction with Oxygen. Issue 4 (7th January 2020)

• Record Type: Journal Article
• Authors: Meng, Caixia; Li, Rongtan; Ning, Yanxiao; Pavlovska, Anastassia; Bauer, Ernst; Fu, Qiang; Bao, Xinhe
• Is Part Of: ChemCatChem. Volume 12:Issue 4(2020)
• Page Start: 1036
• Page End: 1045
• Publication Date: 2020-01-07
• Subjects: Tungsten carbide -- W(110) -- LEEM -- LEED -- Surface segregation -- CVD; Catalysis -- Periodicals; 541.39505
• DOI: 10.1002/cctc.201901755
• Languages: English
• ISSNs: 1867-3880

Abstract

Abstract: Construction of model metal carbide surfaces is essential for surface catalysis studies over carbide‐based catalysts. Here, well‐controlled growth of tungsten carbide (WCx ) layers on W(110) including carbon‐rich R(15×3)‐C/W(110) and carbon‐poor R(15×12)‐C/W(110) structures has been clearly demonstrated using chemical vapor deposition (CVD) on a clean W(110) surface or carbon segregation from the bulk. Low‐energy electron microscopy (LEEM) and micro‐region LEED (μ‐LEED) characterizations confirm that the R(15×12) structure forms first and then transforms to the R(15×3) structure by incorporating more carbon atoms in the CVD or surface segregation processes. Oxidation of the WCx /W(110) surfaces in O2 atmosphere removes surface carbon atoms, driving the structural transformation from R(15×3) to R(15×12) first and then to a two‐dimensional oxide surface. Our work provides a clear guide for well‐controlled growth of model WCx catalysts and the structural transformation between them. Abstract : Well‐controlled growth of tungsten carbide (WCx ) layers on W(110) including carbon‐rich R(15×3)‐C/W(110) and carbon‐poor R(15×12)‐C/W(110) structures using chemical vapor deposition (CVD) or carbon segregation from the bulk have been clearly demonstrated by low‐energy electron microscopy (LEEM) and micro‐region LEED (μ‐LEED). Oxidation of the WCx /W(110) surfaces in O2 atmosphere removes surface carbon atoms, driving the structural transformation from R(15×3) to R(15×12), and to a two‐dimensional oxide surface.