Sabaithip Tungkamani

This work investigates the effect of Co incorporation on the physicochemical properties and dry reforming of methane (DRM) performance of Ni catalysts supported on surface-modified γ-Al₂O₃ containing 9 wt% MgO and 1 wt% ZrO₂ (MS). Bimetallic catalysts containing 5 and 10 wt% Co with a fixed Ni loading of 10 wt% were prepared by co-impregnation. H₂-TPR and H₂-TPD analyses revealed the Co incorporation reducibility and hydrogen adsorption–desorption characteristics of the catalysts. These changes were accompanied by enhanced DRM activity and increased H₂/CO ratios, which may reflect changes in the contributions of competing reactions, including the reverse water–gas shift reaction. Although 10Ni10Co/MS exhibited the highest CH₄ and CO₂ consumption rates and H₂/CO ratio, its enhanced activity was accompanied by more-pronounced graphitic carbon features and greater catalytic deactivation. In contrast, 10Ni5Co/MS maintained more stable catalytic performance while retaining improved reactant utilization and H₂/CO ratio. These findings suggest that controlled Co incorporation provides a favorable balance between DRM activity and resistance to carbon-associated deactivation, with 5 wt% Co providing the best activity–stability balance among the investigated catalysts.

In this work, a rational catalyst design based on interfacial architecture engineering is proposed for low-temperature dry methane reforming (DMR) at 550 °C. Ni-based catalysts containing 10 wt% Ni were developed on a γ-Al₂O₃ support modified with 9 wt% MgO–1 wt% ZrO₂. Zirconia promoters were introduced either by dry impregnation or via an ammonia vapor-assisted route to construct a Ni–NiO–ZrO₂ interfacial network. The effects of ZrO₂ content (0, 1, and 3 wt%) and synthesis route on metal–support interactions, oxygen mobility, and coke resistance were systematically investigated. ZrO₂ promotion increased the fraction of reducible Ni species and preferentially enhanced CO₂ activation, thereby promoting the reverse water–gas shift (RWGS) reaction and lowering the H₂/CO ratio. In contrast, ammonia vapor-assisted preparation induced the formation of an LDH-derived Ni–NiO–ZrO₂ surface network, which increased the concentration of surface-accessible Ni species, suppressed excessive zirconia coverage, and significantly improved apparent oxygen mobility. These synergistic structural features are consistent with enhanced oxygen-assisted carbon removal and improved coke management through regulation of the nature of carbon species, leading to more balanced activation of CH₄ and CO₂. Overall, this study provides insights into interfacial structure–performance relationships for designing efficient Ni-based catalysts for CO₂ utilization.

This study investigates the development of Ni-based catalysts for low-temperature dry methane reforming (DMR) at 550 °C. The catalysts were prepared by dispersing Ni on γ-Al₂O₃ modified with 9 wt% MgO and 1 wt% ZrO₂, while 10 wt% Ni–x wt% ZrO₂ promoters (0, 1, and 3 wt%) were introduced using the incipient wetness impregnation method. A Ni–NiO–ZrO₂ surface network was generated on the 10 wt% Ni–3 wt% ZrO₂ catalyst via an ammonia vapor–assisted impregnation route. The ZrO₂ promoter strengthened the metal–support interaction, which increased the total amount of reducible Ni while shifting the reduction to higher temperatures. This modification also promoted CO₂ activation relative to CH₄, thereby enhancing the RWGS pathway and lowering the H₂/CO ratio. In contrast, the Ni–NiO–ZrO₂ network formed through the ammonia-assisted method increased the concentration of surface-accessible Ni, reduced excessive coverage by ZrO₂, and significantly improved oxygen mobility. These features facilitated continuous oxygen transfer, enhanced coke oxidation, and ensured a more balanced activation of both reactants. Overall, the combined structural and functional synergies achieved through promoter optimization and the ammonia vapor–assisted preparation method resulted in superior catalytic activity and selectivity for DMR at 550 °C.

Ni-based catalysts have been widely used for the CO₂ reforming of methane (CRM) process, but deactivation is their main problem. This study created an alternative electronic Ni-NiO-CeO₂ interaction on the surface of 5 wt% Ni-5 wt% CeO₂/Al₂O₃-MgO (5Ni5Ce(xh)/MA) catalysts to enhance catalytic potential simultaneously with coke resistance for the CRM process. The Ni-NiO-CeO₂ network was developed on Al₂O₃-MgO through layered double hydroxide synthesis via our ammonia vapor diffusion impregnation method. The physical properties of the fresh catalysts were analyzed employing FESEM, N₂ physisorption, and XRD. The chemical properties on the catalyst surface were analyzed employing H₂-TPR, XPS, H₂-TPD, CO₂-TPD, and O₂-TPD. The CRM performances of reduced catalysts were evaluated at 600 °C under ambient pressure. Carbon deposits on spent catalysts were determined quantitatively and qualitatively by TPO, FESEM, and XRD. Compared to 5 wt% Ni-5 wt% CeO₂/Al₂O₃-MgO prepared by the traditional impregnation method, the electronic interaction of the Ni-NiO-CeO₂ network with the Al₂O₃-MgO support was constructed along the time of ammonia diffusion treatment. The electronic interaction in the Ni-NiO-CeO₂ nanostructure of the treated catalyst develops surface hydroxyl sites with an efficient pathway of OH* and O* transfer that improves catalytic activities and coke oxidation.

The effect of different active phases of Fe/SiO₂ catalyst on the physio-chemical properties and the catalytic performance in CO₂ hydrogenation under mild conditions (at 220 °C under an ambient pressure) was comprehensively studied in this work. The Fe/SiO₂ catalyst was prepared by an incipient wetness impregnation method. Hematite (Fe₂O₃) in the calcined Fe/SiO₂ catalyst was activated by hydrogen, carbon monoxide, and hydrogen followed by carbon monoxide, to form a metallic iron (Fe/SiO₂-h), an iron carbide (Fe/SiO₂-c), and a combination of a metallic iron and an iron carbide (Fe/SiO₂-hc), respectively. All activated catalysts were characterized by XRD, Raman spectroscopy, N₂ adsorption–desorption, H₂-TPR, CO-TPR, H₂-TPD, CO₂-TPD, CO-TPD, NH₃-TPD, and tested in a CO₂ hydrogenation reaction. The different phases of the Fe/SiO₂ catalyst are formed by different activation procedures and different reducing agents (H₂ and CO). Among three different activated catalysts, the Fe/SiO₂-c provides the highest CO₂ hydrogenation performance in terms of maximum CO₂ conversion, as well as the greatest selectivity toward long-chain hydrocarbon products, with the highest chain growth probability of 0.7. This is owing to a better CO₂ and CO adsorption ability and a greater acidity on the carbide form of the Fe/SiO₂-c surface, which are essential properties of catalysts for polymerization in FTs.

In this paper, the 10 wt% Ni/Al₂O₃-MgO (10Ni/MA), 5 wt% Ni-5 wt% Ce/Al₂O₃-MgO (5Ni5Ce/MA), and 5 wt% Ni-5 wt% Co/Al₂O₃-MgO (5Ni5Co/MA) catalysts were prepared by an impregnation method. The effects of CeO₂ and Co doping on the physicochemical properties of the Ni/Al₂O₃-MgO catalyst were comprehensively studied by N₂ adsorption-desorption, X-ray diffraction (XRD), transmission electron microscopy (TEM), H₂ temperature programmed reduction (H₂-TPR), CO₂ temperature programmed reduction (CO₂-TPD), and thermogravimetric analysis (TGA). The effects on catalytic performance for the combined steam and CO₂ reforming of methane with the low steam-to-carbon ratio (S/C ratio) were evaluated at 620 °C under atmospheric pressure. The appearance of CeO₂ and Co enhanced the oxygen species at the surface that decreased the coke deposits from 17% for the Ni/MA catalyst to 11–12% for the 5Ni5Ce/MA and 5Ni5Co/MA catalysts. The oxygen vacancies in the 5Ni5Ce/MA catalyst promoted water activation and dissociation, producing surface oxygen with a relatively high H₂/CO ratio (1.6). With the relatively low H₂/CO ratio (1.3), the oxygen species at the surface was enhanced by CO₂ activation-dissociation via the redox potential in the 5Ni5Co/MA catalyst. The improvement of H₂O and CO₂ dissociative adsorption allowed the 5Ni5Ce/MA and 5Ni5Co/MA catalysts to resist the carbon formation, requiring only a low amount of steam to be added.

A novel dual Ni-based catalytic process (DCP) to control the H₂/CO ratio of 2 in the syngas product within one step at temperature 2 reforming of methane (CSCRM) reaction and the exothermic ultra-high-temperature water–gas shift (UHT-WGS) reaction work continuously. During the process, the H₂/CO ratio is raised suddenly at UHT-WGS after the syngas is produced from CSCRM, and CSCRM utilizes the heat released from UHT-WGS. Due to these features, DCP is more compact, enhances energy efficiency, and thus decreases the capital cost compared to reformers connecting with shift reactors. To prove this propose, the DCP tests were done in a fixed-bed reactor under various conditions (temperature = 500, 550, and 600 °C; the feed mixture (CH₄, CO₂, H₂O, and N₂) with H₂O/(CH₄ + CO₂) ratio = 0.33, 0.53, and 0.67). According to the highest CH₄ conversion (around 65%) with carbon tolerance, the recommended conditions for producing syngas with the H₂/CO ratio of 2 as a feedstock of Fischer–Tropsch synthesis include the temperature of 600 °C and the H₂O/(CH₄ + CO₂) ratio of 0.53.

This research focus on catalytic hydrotreating of Jatropha Bio-oil derived fast pyrolysis into biofuel was investigated to determine the effects of the supported type (Al₂O₃ TiO₂ and Al₂O₃-TiO₂ mix-oxide) and of the variables temperature (300-340 °C). The synthesized catalysts were prepared by sol-gel method for support and wet-impregnation with solution promoter on support, and characterization by BET NH₃-TPD XRD and NO-TPD for active site analysis of catalysts. The reaction was carried out in a Parr batch reactor under H₂ atmosphere about 50 bar for 2 h. The catalytic activity was evaluated for % fatty acid conversion (%FFA), %HDO, %selective to paraffin/olefin products. The results showed that the CMA gave the %FFA is highest, but low selective products, then the CMT gave the % HDO high than CMA, while the mixed-oxide were proving the %HDO, %FFA conversion and % selective is increasing because the TiO₂ incorporated with Al₂O₃ effect to increase the amount of rim site, it’s active site for HYD partway.

This paper aims to study the effect of raschig ring packing patterns using Computational Fluid Dynamics (CFD). CFD module of particle tracing was established to measure particles diffusing through the packed bed. The support raschigs catalyst was modeled in three patterns within a tubular reactor – namely, vertical staggered, chessboard staggered and reciprocal staggered pattern. A case study of Dry Methane Reforming (DMR) was investigated at 600°C, 1 atm. The study of Mean Resident Time (MRT) and E(t) function were investigated to identify the packing pattern performance. The results showed that the minimum value of the E(t), which means the flow behavior, was close to ideal plug flow behavior. MRT can be used to systematically identify the deviation from the ideal plug flow reactor of the three different packing patterns.