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Complete Formaldehyde Removal over 3D Structured Na 1.1 Mn 4 O 8 @Mn 5 O 8 Biphasic‐Crystals
Author(s) -
Zhang Chunlei,
Liu Guojuan,
Wu Ping,
Zeng Gaofeng,
Sun Yuhan
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.202000449
Subject(s) - catalysis , calcination , manganese , nanorod , formaldehyde , oxidation state , inorganic chemistry , nanosheet , oxygen , chemistry , materials science , crystallography , nanotechnology , biochemistry , organic chemistry
Abstract With the increasing concerns on the formaldehyde (HCHO) hazard, the efficient oxidation of HCHO over affordable and harmless catalyst is of significant practical interest. Herein, the intermediate state of Mn 5 O 8 −Na 1.1 Mn 4 O 8 (Na−Mn 5 O 8 ) biphasic‐crystal catalyst, which features Na 1.1 Mn 4 O 8 ‐nanosheet@ Mn 5 O 8 ‐nanorod interconnected 3D structure, is successfully fabricated through the anaerobic calcination of manganite followed by alkali treatment. The resultant Na−Mn 5 O 8 exhibits 100 % conversion of HCHO (150 ppm and 60000 h −1 ) and reliable stability (50 h) at 90 °C under demanding water‐free feed conditions, which is superior to that of the reference samples of Mn 5 O 8 , Na 1.1 Mn 4 O 8 , MnO 2 and Na−MnO 2 . The experimental results demonstrate that the abundant structure defects (oxygen vacancies) on Na−Mn 5 O 8 , which may locate along the phase interfaces / shared‐edges of Mn 5 O 8 nanorods and Na 1.1 Mn 4 O 8 nanosheets, significantly enhance the active oxygen species and finally contribute to the high activity for HCHO oxidation. Furthermore, the 3D structure of Na−Mn 5 O 8 favors mass transfer and fully exposing active sites for the HCHO adsorption and conversion. These findings reveal a way to enhance the catalytic activity of metal oxides via controlling the intermediate state of heteropical crystals.