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Visualizing Formation of Tungsten Carbide Model Catalyst and its Interaction with Oxygen
Author(s) -
Meng Caixia,
Li Rongtan,
Ning Yanxiao,
Pavlovska Anastassia,
Bauer Ernst,
Fu Qiang,
Bao Xinhe
Publication year - 2020
Publication title -
chemcatchem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.497
H-Index - 106
eISSN - 1867-3899
pISSN - 1867-3880
DOI - 10.1002/cctc.201901755
Subject(s) - tungsten carbide , catalysis , tungsten , carbide , oxygen , materials science , heterogeneous catalysis , chemical engineering , chemistry , metallurgy , organic chemistry , engineering
Construction of model metal carbide surfaces is essential for surface catalysis studies over carbide‐based catalysts. Here, well‐controlled growth of tungsten carbide (WC x ) 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 WC x /W(110) surfaces in O 2 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 WC x catalysts and the structural transformation between them.