Abstract:N-doped TiO2-SBA-15 (denoted as N-TiO2-SBA-15) material has been successfully synthesized by a two-step procedure. Firstly, TiO2-SBA-15 was prepared by impregnating tetraisopropyl orthotitanate on SBA-15 and followed by calcination at 550°C. In the second step, TiO2-SBA-15 was modified by doping nitrogen with the assistance of urea. The resulting material, N-TiO2-SBA-15, was characterized by XRD, TEM, SEM, N2adsorption/desorption at 77 K, DR UV-Vis, and XPS. The results showed that N-TiO2-SBA-15 material maint… Show more
“…Moreover, the titania presence in the silica mesoporous was evidence by the peak at wavenumber of 1627–1633 cm −1 as Ti–OH bending [ 40 ] and at 803-806 cm −1 as Ti– O –Ti bond [ 41 ]. The wavenumber peak at this research are consistent with those of earlier research [ 3 , 6 , 7 , 21 , [42] , [43] , [44] ]. Fig.…”
Section: Resultssupporting
confidence: 92%
“…Therefore, the good support material is required to ensure that TiO 2 is properly distributed and effective for photodegradation [ 5 ]. Mesoporous silica is among the most preferred support materials [ [6] , [7] , [8] ].…”
“…Moreover, the titania presence in the silica mesoporous was evidence by the peak at wavenumber of 1627–1633 cm −1 as Ti–OH bending [ 40 ] and at 803-806 cm −1 as Ti– O –Ti bond [ 41 ]. The wavenumber peak at this research are consistent with those of earlier research [ 3 , 6 , 7 , 21 , [42] , [43] , [44] ]. Fig.…”
Section: Resultssupporting
confidence: 92%
“…Therefore, the good support material is required to ensure that TiO 2 is properly distributed and effective for photodegradation [ 5 ]. Mesoporous silica is among the most preferred support materials [ [6] , [7] , [8] ].…”
“…In terms of preparation techniques, two methods are commonly employed for obtaining SBA-15 modified with TiO 2 nanocrystals: post-synthesis and one-pot methods. The first one is able to promote the formation of metal oxides in the channels or external surfaces of support, which could block the channels and not allows the easy access of reactant molecules to the reaction sites in the porous matrix [29][30][31][32][33][34][35][36][37][38][39]. In the second one, it occurs the simultaneous addition of the precursors of silica and titanium oxides in the synthesis gel.…”
In this paper, a new synthesis method was proposed to obtain anatase titanium oxide (TiO 2) nanocrystals anchored into SBA-15 molecular sieve, as a matrix assigned by the in-situ anchoring (ISA) method. Pure SBA-15 and modified with TiO 2 nanocrystals at different Si/Ti molar ratios (R = 75, 50, and 25) were structurally characterized by X-ray diffraction (XRD), Micro-Raman and Fourier Transform infrared (FTIR) spectroscopies. Specific surface area, pore volume and average pore diameter were estimated using both Brunauer-Emmett-Teller (BET) and Barrett-Joyner-Halenda (BJH) methods, respectively. Morphological aspects of these samples were observed by means of field emission scanning electron microscopy (FE-SEM) and transmission electron microscopy (TEM). Optical properties were investigated by ultravioletvisible (UV-vis) diffuse reflectance spectroscopy. XRD patterns, Micro-Raman and FT-IR spectra indicate the TiO 2 nanocrystals crystallized in a tetragonal structure anchored into the SBA-15 mesopores. BET and BJH methods prove a large amount of TiO 2 nanocrystals were anchored inside of SBA-15 mesopores due to increase in surface area and average pore size of SBA-15 matrix. FE-SEM and TEM images showed the pure SBA-15 has an elongated hexagon-shaped microstructure, and an average size of 7.34 nm for 2D hexagonal mesopores. Moreover, ISA method was able to avoid blocking of mesopores, in addition promotes a significant increasing the impregnation rate of anatase TiO 2 nanocrystals in SBA-15 matrix. A growth mechanism was proposed in order to explain the stages involved in the formation of TiO 2-SBA mesoporous. UV-vis spectra revealed a dependence of the optical band gap energy (E gap) with the decreasing of Si/Ti molar ratios.
“…Titania (TiO2), is typically used as a photocatalyst due to its redox property in the photoexcited state inducing water splitting reaction [147][148][149][150] . TiO2 has been reported to catalyze CO2 hydrogenation to produce methanol, alone or, as a promoter to improve the selectivity towards methanol by contributing to active metal sites 81,96,151 .…”
Section: Catalysts For Co2 Hydrogenationmentioning
confidence: 99%
“…Silica has been reported as a high stability support for Cu active phase to be used in various hydrogenation and dehydration reactions 46,68,99,157 and it was shown to increase the methanol yield through CO2 hydrogenation by providing additional positive surface charge due to the Cu-SiO2 bonds at the interface 106,158,159 . Mesoporous silica can be prepared with a very high specific surface area (can be more than 700 m 2 /g) and uniform pore size distribution enabling improved dispersion and controllable particle size of the active phase nanoparticles 53,59,147 . High surface area of the support is beneficial not only to obtain a large catalytically active metal surface but also for keeping the active sites isolated from each other which can otherwise interact with each other instead of gas phase reactant molecules 99 .…”
Section: Catalysts For Co2 Hydrogenationmentioning
Hybrid material systems possess multi-functional properties which make them intriguing for the materials science community since very early dates. However, it is not straightforward to produce such material systems. A smart and efficient approach is necessary to extract the desired properties of each component under the desired conditions. This study evolved to its last form primarily around this notion, where the development of a hybrid material is the core of the work. This hybrid material is then further explored for two different applications in the catalysis and drug delivery fields.A nanoassembly was established around a mesoporous silica support. SBA-15 was picked as this support among the other mesoporous silica due to its well-defined pore structure and accessible pore volume. The silica framework was doped with Zr atoms and the pores were partly infiltrated with Cu nanoparticles resulting in a hybrid material with tunable properties. SBA-15 was synthesized by a sol-gel method where a micellar solution was employed as a template for the silica framework. To achieve the doped version, a Zr precursor was added to the synthesis solution. The effects of different synthesis conditions, such as the synthesis catalyst (For a Clsalt) and the Si source (tetraethyl orthosilicate (TEOS) or sodium metasilicate (SMS)) on the characteristics of the final material were investigated. It was observed that these changes in the synthesis conditions yielded different particle morphology, pore size (11-15 nm), and specific surface area (400-700 m 2 /g). Cu nanoparticles (NPs) were grown in the (Zr-)SBA-15 support using infiltration (Inf) or evaporation induced wetness impregnation (EIWI) methods. The infiltration method is based on functionalizing the (Zr-)SBA-15 support surfaces before the Cu ion attachment whereas EIWI is based on slow evaporation of the liquid from the (Zr-)SBA-15 -Cu aqueous suspension. Both methods are designed to yield preferential growth of Cu NPs in the pores with a diameter smaller than 10 nm and in oxidized form.However, depending on the loading method used, different chemical states of the final material were achieved, i.e. Zr content and porous network properties are different.Cu-Zr-SBA-15 nanoassemblies produced under various synthesis conditions were used for the catalytic conversion of CO2 into valuable fuels such as methanol and dimethyl ether (DME). The effect of different chemical states of the catalyst arising from variations in the synthesis parameters was investigated. It was found that the Si precursor (TEOS or SMS) had a considerable impact on the overall performance of the catalyst whereas the Cu iv loading method (Inf or EIWI) changed the catalytic selectivity between DME and methanol. The activity of the catalyst was further investigated in a time-evolution study where the accumulation of each product in the gas phase and the molecular groups attached to the catalyst surface were recorded over time. Accordingly, thermodynamic equilibrium was achieved on the 14th day of the reaction ...
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