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Bimetallic PdNi catalyst on cattail Leaves-Derived nanoporous carbon support for synthesis of partially hydrogenated fatty acid methyl ester (H-FAME)
(2024-06-01)
Longprang, Tripob
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Kaewtrakulchai, Napat
;
Kiatkittipong, Worapon
;
Srifa, Atthapon
;
Chollacoop, Nuwong
Cattail leaves (CL) have been used as a carbon source to synthesize nanoporous carbon (NPC) support with high surface area (S<inf>BET</inf> = 2002.12 m2g−1) via hydrothermal carbonization and potassium hydroxide (KOH) activation. The studied catalysts, including monometallic Pd/NPC and Ni/NPC, and bimetallic PdNi/NPC, were synthesized and characterized by using several techniques (e.g., scanning electron microscopy, transmission electron microscopy, nitrogen sorption, Fourier transform infrared spectroscopy, thermogravimetric analysis, and X-ray diffraction). Their catalytic activity toward partial hydrogenation of palm biodiesel to H-FAME was tested, and the liquid product composition, cloud point, and oxidation stability were determined. The studied catalysts have a high porosity with the S<inf>BET</inf> of approximately 2037.34–2187.96 m2g−1 led to excellent metal dispersion. Although Ni did not show high catalytic activity compared to Pd, Ni incorporated with Pd as PdNi/NPC catalyst significantly increased the cis-C18:1 selectivity and prevented the catalytic deactivation during the partial hydrogenation. The oxidation stability of palm biodiesel feedstock was increased from 13.69 to 17.12 h while the cloud points adversely increased by only 3 degrees from 12 to 15 °C (still lower than 16 °C of the Thai industrial recommendation) with bimetallic PdNi/NPC catalyst. The main benefit of bimetallic PdNi/NPC over monometallic Pd/NPC and Ni/NPC is shown through not only higher C18:2 conversion but also much higher cis-to-trans ratio of C18:1 resulting in higher oxidation stability with acceptable compromise on the cloud point increasing. Consequently, the produced palm H-FAME can be used at a high blend ratio.
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Cattail leaf-derived nitrogen-doped carbons via hydrothermal ammonia treatment for electrocatalytic oxygen reduction in an alkaline electrolyte
(2022-07-12)
Panomsuwan, Gasidit
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Eiad-ua, Apiluck
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Kaewtrakulchai, Napat
;
Seizawa, Ai
;
Ishizaki, Takahiro
Cattail leaf-derived nitrogen-doped carbons (CL-NCs) were prepared by hydrothermal treatment in ammonia solution and subsequent pyrolysis for application as catalysts for the oxygen reduction reaction (ORR). The ammonia concentration was varied at 1.0, 1.5, and 2.0 M to alter the nitrogen doping content. The characterization results revealed that CL-NCs exhibited an amorphous structure, while the density of structural defects increased as the ammonia concentration increased. The CL-NC prepared without hydrothermal ammonia treatment had a nonporous structure with a low specific surface area (5 m2 g−1). With hydrothermal ammonia treatment, CL-NCs exhibited a micro–mesoporous structure with a higher surface area (113–496 m2 g−1); however, the surface area was significantly diminished at higher ammonia concentrations due to the deterioration of the pore structure. The nitrogen-doping content in CL-NCs varied from 0.65 to 1.55 atom% with the predominant ratios of pyridinic-N and graphitic-N. For electrochemical evaluation in an alkaline electrolyte (0.1 M KOH), CL-NC prepared at an ammonia concentration of 1.0 M showed the highest ORR activity among all samples, as indicated by the most positive onset potential (−0.05 V vs. Ag/AgCl) and half-wave potential (−0.22 V vs. Ag/AgCl) as well as the highest diffusion-limiting current density with a more favorable reduction via a direct four-electron pathway (n = 3.23–3.52). The ORR activity of CL-NCs had a similar trend to their specific surface area rather than nitrogen doping content, indicating the important role of surface area and porosity in enhancing the ORR activity. Moreover, it possessed excellent stability under long-term operation and exposure to methanol. The results obtained in this work could be helpful information for the further development and utilization of biomass-derived NCs for ORR catalysts.
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Influence of hydrothermal-carbonization process on biochar properties from cattail weed waste
(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
Biochars have been successfully synthesized from Cattail leave (CL) via hydrothermal and carbonization process. The experimental work described has focused on physical properties of biochars produced from Cattail leaves at 160, 180 and 200°C for 8, 12 and 24 h for hydrothermal and substituted to carbonization at 700°C for 2 h. The influences of hydrothermal and carbonization on the pore structure, surface functional groups and the product yield was also investigated by characterization using Scanning Electron Microscope (SEM) and Fourier Transform Infrared Spectroscopy, respectively. Although the morphologies of cell structures were maintained in the hydrothermal and carbonization, it was found that the yield of produced biochar was decreased with increase of the hydrothermal temperature and time. The images from SEM showed that the pore structures are quite roughness on their external surface of biochar and the functional group of their surface area has most of pure carbon content (59-65 wt%).
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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 700oC 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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