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Monolayer Tantalum Oxide on Mesoporous Silica Substrate
Author(s) -
Kondo Junko N.,
Yamazaki Hiroshi,
Ishikawa Asako,
Osuga Ryota,
Takao Sho,
Yokoi Toshiyuki,
Kikkawa Soichi,
Teramura Kentaro,
Tanaka Tsunehiro
Publication year - 2016
Publication title -
chemistryselect
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.437
H-Index - 34
ISSN - 2365-6549
DOI - 10.1002/slct.201600507
Subject(s) - x ray photoelectron spectroscopy , monolayer , analytical chemistry (journal) , mesoporous silica , tantalum , amorphous solid , mesoporous material , materials science , substrate (aquarium) , transmission electron microscopy , absorption spectroscopy , chemistry , crystallography , catalysis , chemical engineering , nanotechnology , organic chemistry , oceanography , geology , engineering , metallurgy , physics , quantum mechanics
Monolayer Ta 2 O 5 was fabricated on mesoporous silica (SBA‐15) substrate by the reaction of Ta(OEt) 5 with surface hydroxyl groups on silica. The monolayer was defined at the saturation amount of Ta(OEt) 5 anchored on SBA‐15 surface in a series of increment of the feed amount the precursor, which was confirmed by elemental (inductively coupled plasma‐atomic emission, ICP‐AE) analysis of the product (Ta 2 O 5 /SBA‐15). Ta/Si ratio of Ta 2 O 5 /SBA‐15 with saturated amount of Ta was 0.11–0.12. X‐ray photoelectron spectroscopy (XPS) analysis of Ta/Si ratio of a series of samples by using the Ta4 f and Si2p signals met agreement with the gradual increase and the saturation at about 0.11–0.12, as well as the local elemental analysis by energy dispersive X‐ray spectrometry (EDS) using transmission electron microscopy (TEM). The absorption edge of UV‐vis. diffuse reflectance spectra of a series of samples appeared very sharp, decreasing the excitation energy from 5.1 to 4.7 eV by increasing the Ta/Si ratio from 0.01 to 0.11−0.12. X‐ray absorption near edge fine structure (EXAFS) indicated the inhomogeneous (amorphous) feature of Ta 2 O 5 phase on SBA‐15 with Ta octahedral species. The unique surface property of monolayer Ta 2 O 5 /SBA‐15 was characterized by infrared (IR) spectroscopy and catalytic reactions.