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A CeCoO x Core/Nb 2 O 5 @TiO 2 Double‐Shell Nanocage Catalyst Demonstrates High Activity and Water Resistance for Catalytic Combustion of o ‐Dichlorobenzene
Author(s) -
Ling Weitong,
Zhao Haijun,
Wu Shilin,
Tang Zhicheng,
Zha Fei
Publication year - 2021
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.202100392
Subject(s) - catalysis , nanocages , hydrothermal circulation , shell (structure) , materials science , thermal stability , hydrothermal synthesis , crystallography , chemical engineering , chemistry , composite material , organic chemistry , engineering
A series of catalysts with different core‐shell structures has been successfully prepared by a hydrothermal method. They consisted of CeCoO x @TiO 2 (single shell), CeCoO x @Nb 2 O 5 (single shell) and CeCoO x @Nb 2 O 5 @TiO 2 (double shell) core‐shell nanocages and CeCoO x nanocages, in which CeCoO x was the core and TiO 2 and Nb 2 O 5 were shells. The influence of the core‐shell structure on the catalytic performance of o ‐dichlorobenzene was investigated by activity, water‐resistance, and thermal stability tests as well as catalyst characterization. The temperatures corresponding to 90 % conversion of o ‐dichlorobenzene ( T 90 ) of CeCoO x , CeCoO x @TiO 2 , CeCoO x @Nb 2 O 5 , and CeCoO x @Nb 2 O 5 @TiO 2 catalysts were 415, 383, 362 and 367 °C, respectively. CeCoO x @Nb 2 O 5 exhibited excellent catalytic activity, mainly owing to the special core‐shell structure, large specific surface area, abundant activity of Co 3+ , Ce 3+ , Nb 5+ , strong reducibility, and more active oxygen vacancies. It can be seen that the Nb 2 O 5 coating can greatly improve the catalytic activity of the catalyst. In addition, due to the protective effect of the TiO 2 shell on CeCoO x , CeCoO x @Nb 2 O 5 @TiO 2 catalysts exhibited outstanding thermal and hydrothermal stability for 20 hours. The T 90 of CeCoO x @Nb 2 O 5 @TiO 2 was slightly lower than that of CeCoO x @Nb 2 O 5 , but it had higher stability and hydrothermal stability. Furthermore, possible reaction pathways involving the Mars‐van‐Krevelen (MvK) and Langmuir‐Hinshelwood (L−H) models were deduced based on studies of the temperature‐programmed desorption of O 2 (O 2 ‐TPD), X‐ray photoelectron spectroscopy (XPS), and in situ diffuse reflectance FTIR spectroscopy (DRIFTS) characterization.