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A combined DFT-Experimental study on FSP-made Ru/Ti-SiO2 catalysts for CO2 methanation
(2025-07-01)
Mekasuwandumrong, Okorn
;
Saelee, Tinnakorn
;
Noppakhun, Jakapob
;
Rittiruam, Meena
;
Khajondetchairit, Patcharaporn
Flame spray pyrolysis (FSP) was employed to synthesize Ti-modified SiO₂ in a single step, serving as the support for Ru-based catalysts in CO₂ methanation reactions. The addition of Ti led to the formation of anatase and rutile TiO₂ phases, enhancing the catalytic activity of Ru/Ti-SiO₂ catalysts. Benchmarking between Ru/Ti-SiO₂ catalysts of various Ti concentrations prepared using one-step FSP techniques indicated significantly higher catalytic activity for the impregnation-made catalysts compared to the FSP-made ones, where diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) revealed different CH₄ formation mechanisms between two techniques. For FSP-made catalysts, it predominantly occurred through the CO route, whereas the impregnation-made proceed via both the dissociative adsorption of CO₂ (CO route) and through surface formate species formation. To explain the effect of Ti loading on Ru/SiO₂ catalysts, a multiscale analysis combining density functional theory (DFT) and microkinetic modeling was performed to study the adsorption behavior of CO₂ on different catalysts. The results revealed that a high amount of Ti reduced the adsorption strength of CO₂ on Ru/SiO₂ catalysts, indicating a modified interaction between CO₂ and the catalyst surface.
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Alkanolamine-Grafted and Copper-Doped Titanium Dioxide Nanosheets-Graphene Composite Heterostructure for CO2 Photoreduction
(2023-11-13)
Karawek, Apisit
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Kitjanukit, Nutkamol
;
Neamsung, Wannisa
;
Kinkaew, Chonlathon
;
Phadungbut, Poomiwat
CO<inf>2</inf> photoreduction is an intriguing approach to carbon capture, utilization, and storage (CCUS). It relies on an effective photocatalyst to generate photoinduced electrons that incorporate carbon dioxide (CO<inf>2</inf>), yielding fuel products, e.g., methane, methanol, and ethanol. The heterostructure of titanium dioxide nanosheets (TNS) and graphene oxide (GO) is a sandwich-type composite consisting of two 2-dimensional nanostructures (2D-2D). It was demonstrated as an excellent candidate for CO<inf>2</inf> photoreduction due to its outstanding charge separation ability. This research studied the photoactivity of alkanolamine-grafted TNS and alkanolamine-grafted and copper-doped TNS/GO composites. In the first experiment, triethanolamine-grafted TNS (TEA-TNS) exhibited the best ability in CO<inf>2</inf> photoreduction compared to monoethanolamine- and diethanolamine-grafted TNS (MEA-TNS and DEA-TNS) due to the base-catalyzed hydration nature of CO<inf>2</inf>-TEA interactions. In the second experiment, we studied the photoactivity of four composites, including copper-doped TNS/GO (Cu-TNS/GO), TEA-[Cu-TNS/GO] (grafting TEA on Cu-TNS/GO), Cu-[TEA-TNS]/GO (doping Cu on TEA-TNS/GO), and TEA-Cu-TNS/GO (one-step hydrothermal synthesis with the Cu precursor, TEA, and GO). TEA-[Cu-TNS/GO] showed the best photoactivity since TEA was added last to the heterostructures, which benefited in avoiding side chelation reactions between TEA and Cu ions and ensuring TEA exposure to CO<inf>2</inf>
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Determination of Binary Gas Mixtures by Measuring the Resonance Frequency in a Piezoelectric Tube
(2022-02-01)
Keeratirawee, Kanchalar
;
Hauser, Peter C.
The composition of gas mixtures may be determined via changes of the speed of sound. As this affects the resonance frequency of the gas inside a tube, indirect measurements through a frequency analysis are also possible. It is demonstrated that this may be carried out with unprecedented simplicity by the novel employment of a piezoelectric tube which serves at the same time as a resonance tube and as transducer into the electronic domain. Experiments were run using a simple diecast aluminum box as the measuring cell, inside which the piezoelectric tube made from lead zirconium titanate with 30-mm length and 5.35-mm inner diameter was suspended. A small loudspeaker placed into the cell served for excitation of the resonance. Peak frequencies between 3910 and 14,590 Hz (for pure CO<inf>2</inf> and He, respectively) were obtained. Two component mixtures of O<inf>2</inf>/N<inf>2</inf>, CO<inf>2</inf>/N<inf>2</inf>, and He/N<inf>2</inf> at various composition were tested. A linear frequency change from 4790 to 5100 Hz was observed when going from pure O<inf>2</inf> to pure N<inf>2</inf> .
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Nanoporous carbon from Cattial leaves for carbon dioxide capture
(2019-01-01)
Smuthkochorn, Araya
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Katunyoo, Nardnutda
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Kaewtrakulchai, Napat
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Atong, Duangduen
;
Soongprasit, Kanit
Reducing anthropogenic CO<inf>2</inf> emissions and lowering the concentration of greenhouse gases in the atmosphere have quickly become one of the most urgent environmental issues of our age. Carbon capture and storage (CCS) is the option for reducing these harmful CO<inf>2</inf> emissions. While a variety of technologies and methods have been developed, the separation of CO<inf>2</inf> from gas streams is still a critical issue. Apart from establishing new techniques, the exploration of capture materials with high separation performance and low capital cost are of paramount importance. Nanoporous carbon derived from leaf of cattail flower that found in all areas throughout Thailand, the biomass was previously pyrolyzed at 500 to 700<sup>o</sup>C and the produced chars were further activated with NaOH, KOH, Na<inf>2</inf>CO<inf>3</inf> and K<inf>2</inf>CO<inf>3</inf> subsequently. Afterwards, the resulting materials were characterized by Scanning electron microscopy, Fourier-transform infrared spectroscopy and Raman scattering measurement. From this investigation, produced activated carbon will be efficient as an option for CO<inf>2</inf> emission control.

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