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Sutarawadee Monyanon Apanee Luengnaruemitchai Sangobtip Pongstabodee 《International Journal of Hydrogen Energy》2010
A series of Pt–Au catalysts prepared by co-precipitation (CP) and single step sol-gel (SSG) methods was investigated for selective CO oxidation. The characteristics of the prepared catalysts were determined by XRD, BET surface area, SEM, H2-TPR, chemisorption analysis, and FTIR. The simulated reformatted gas consisted of 1% CO, 1% O2, 0% to 10% H2O, 0–20% CO2, and 40% H2 in He balance. The operating temperature range was varied from 50 °C to 190 °C at atmospheric pressure. The experimental results elucidated that the catalytic preparation method had a significant effect on the catalyst characteristics and its activity. The catalytic performance over PtAu/Ce1Zn1O2 prepared by co-precipitation was higher than that of PtAu/CeO2 and PtAu/ZnO because of the incorporation of Ce4+ ions and the Zn2+ ions in the lattice. To encourage better catalytic performance, the catalysts should be calcined at 500 °C for 5 h and pretreated in a H2 atmosphere. The CO conversion for the single- and double-stage reaction was reduced when adding water vapor and CO2 to the feedstream; the water vapor and CO2 molecules compete for the adsorption with CO on the active sites of the catalysts. During the deactivation test for 60 h, the CO conversion and selectivity are maintained. 相似文献
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Khampol Sirichaiprasert Sangobtip Pongstabodee Apanee Luengnaruemitchai 《Journal of the Chinese Institute of Chemical Engineers》2008,39(6):597-607
Single- and double-stage catalytic preferential CO oxidation (CO-PrOx) over-Fe2O3-promoted CuO–CeO2 in a H2-rich stream has been investigated in this work. The catalyst was prepared by the urea-nitrate combustion method and was characterized by X-ray diffractometer (XRD), X-ray fluorescence (XRF), Brunauer–Emmet–Teller (BET), transmission electron microscope (TEM), and scanning electron microscope (SEM). The catalytic activity tests were carried out in the temperature range of 50–225 °C under atmospheric pressure. The results of the single-stage reaction indicated that complete CO oxidation was obtained when operating at a O2/CO ratio of 1.5, W/F ratio of 0.36 g s/cm3, and at a reaction temperature of 175 °C. At these conditions, H2 consumption in the oxidation was estimated at 58.4%. Applying the same conditions to the double-stage reaction, complete CO oxidation was found and H2 consumption in the oxidation was reduced about 4.9%. When decreasing the double-stage reaction temperature to 150 °C, the results elucidated that CO could be converted to CO2 completely while H2 consumption in the oxidation was further reduced to 33.5%. A temperature blocking 22 factorial design has been used to describe the importance of the factors influencing the catalytic activity. The factorial design was according to the experimental results. When adding CO2 and H2O in feed, reduction of CO conversion for single- and double-stage reaction is obtained due to a blocking of CO2 and H2O at a catalytic active site. Comparing CO conversion obtained when operating with/without CO2 and H2O in feed for single- and double-stage reaction, less reduction is achieved when operating in double-stage reaction. 相似文献
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Sutarawadee Monyanon Sangobtip Pongstabodee Apanee Luengnaruemitchai 《Journal of the Chinese Institute of Chemical Engineers》2007,38(5-6):435-441
The objective of this paper was to study a preferential oxidation (PROX) of carbon monoxide over monometallic catalysts including Pt, Au and Pt–Au bimetallic catalyst supported on ceria in hydrogen-rich reformate. Single step sol–gel method (SSG) and impregnation on sol–gel method (ISG) were chosen for the preparation of the catalysts. The characteristics of these catalysts were investigated by X-ray diffractometer (XRD), Brunauer–Emmet–Teller (BET) method, transmission electron microscope (TEM), scanning electron microscope (SEM) and temperature-programmed reduction (TPR). The XRD patterns of the catalysts showed only the peaks of ceria crystallite and no metal peak appeared. From TEM images, the active components were seen to be dispersed throughout the ceria support. The TPR patterns of PtAu/CeO2 catalyst prepared by SSG showed the reduction peaks were within a low temperature range and therefore, the catalysts prepared by SSG exhibited excellent catalytic activity for preferential oxidation of CO. Bimetallic Pt–Au catalyst improved the activity (90% conversion and 50% selectivity at 90 °C) because of the formation of a new phase. When the metal content of (1:1) PtAu/CeO2 catalyst prepared by SSG was increased, the CO conversion did not change much while the selectivity decreased in the low temperature range (50–90 °C). The CO conversion increased with increasing W/F ratio. The presence of CO2 and H2O had a negative effect on CO conversion and selectivity due to blocking of carbonate and water on active sites. 相似文献
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Srisin Eaimsumang Sujitra Wongkasemjit Sangobtip Pongstabodee Siwaporn Meejoo Smith Sukritthira Ratanawilai Nuwong Chollacoop Apanee Luengnaruemitchai 《中国稀土学报(英文版)》2019,37(8):819-828
Ceria(CeO_2)supports,synthesized by hydrothermal treatment with different synthesis time(CeO_2-X h,where X is the synthesis time in h)in the presence of the surfactant cetyltrimethyl ammonium bromide,were used as supports for gold(Au)catalysts.The synthesis time significantly affects the morphological structure and crystallite size of CeO_2,where CeO_2-2 h has the smallest crystallite size with coexisting nanorods and nanoparticles.Transmission electron microscopy analysis confirms the morphology of CeO_2 with distinctive(110),(100)and(111)planes,in agreement with interplanar spacings of 0.19,0,27 and 0.31,respectively.However,the morphology of CeO_2-8 h and CeO_2-48 h is mainly a truncated octahedral with crystal planes(111)and(100)accompanied by an interplanar spacing of 0.31 and0.27 nm,respectively.The CeO_2-X h supports and those with a 3 wt%Au loading(Au/CeO_2-X h)were investigated in the oxidative steam reforming of methanol at temperatures between 200 and 400 ℃.The Au/CeO_2-2 h gave the highest methanol conversion level and hydrogen yield at a low temperature of 250 ℃.This superior catalytic performance results from the good interaction between the metal and support and the well-distributed Au species on the CeO_2 support. 相似文献
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Sangobtip Pongstabodee Sutarawadee Monyanon Apanee Luengnaruemitchai 《International Journal of Hydrogen Energy》2012
The catalytic performance for the preferential oxidation of CO over a 1% (w/w) PtAu/CeO2–ZnO catalyst prepared by co-precipitation was investigated using a full 2k factorial design with three central points and a 95% confidence interval, in order to screen for the importance of the operating temperature (°C) and the H2O and CO2 contents (%) in the simulated reformate gas on the CO conversion and selectivity. The catalyst was characterized by TEM, BET, XRD and FTIR. The temperature and CO2 content had a significant influence on the conversion, whilst the selectivity depended on the temperature only. A face-centered central composite design was then used to evaluate the optimal conditions by simultaneously considering the maximal conversion, selectivity and constraints of the composition of realistic reformate gas. The difference in the estimated response and the experimental one was within ±2% and ±3% for routing simulated and realistic reformate gases, respectively. 相似文献
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Nutthavich Thouchprasitchai Apanee Luengnaruemitchai Sangobtip Pongstabodee 《Journal of Industrial and Engineering Chemistry》2013,19(5):1483-1492
Water-gas shift reaction was investigated over Cu–Zn, Cu–Fe and Cu–Zn–Fe composite-oxide catalysts at atmospheric pressure from 200 to 375 °C in terms of reducing the CO content with maximal H2 yield. The Cu0.15ZnFe2 spinel catalyst expressed a higher CO conversion level and H2 yield at a lower temperature compared to the Cu0.15Zn and Cu0.15Fe catalysts. Adding H2O to the feed up to 30% (v/v), but not above, increased the CO reduction level, presumably by increasing the hydroxyl species to react with the adsorbed CO. Increasing the W/F ratio to 0.24 g s cm?3 increased the CO conversion level to 0.76 at 275 °C with the Cu0.15ZnFe2 catalyst, and could be further increased to 0.86 at 350 °C by increasing the Cu molar ratio to 0.30 (Cu0.30ZnFe2). Nevertheless, increasing the Cu molar content to 0.50 reduced the CO conversion level. No requirement for adding O2 when using the Cu0.30ZnFe2 catalyst at >260 °C was observed. Increasing the CO content in the reactant decreased its conversion level. The performance of the Cu0.30ZnFe2 catalyst was stable over a test period in a CO-rich condition. No undesired product was detected, suggesting a higher selectivity for hydrogen production with a low CO content. 相似文献
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Sangobtip Pongstabodee Sutarawadee Monyanon Apanee Luengnaruemitchai 《Journal of Industrial and Engineering Chemistry》2012,18(4):1272-1279
The production of hydrogen (H2) with a low concentration of carbon monoxide (CO) via steam reforming of methanol (SRM) over Au/CuO, Au/CeO2, (50:50)CuO–CeO2, Au/(50:50)CuO–CeO2, and commercial MegaMax 700 catalysts were investigated over reaction temperatures between 200 °C and 300 °C at atmospheric pressure. Au loading in the catalysts was maintained at 5 wt%. Supports were prepared by co-precipitation (CP) whilst all prepared catalysts were synthesized by deposition–precipitation (DP). The catalysts were characterized by Brunauer–Emmett–Teller (BET) surface area, X-ray diffraction (XRD), temperature-programmed reduction (TPR), and scanning electron microscopy (SEM). Au/(50:50)CuO–CeO2 catalysts expressed a higher methanol conversion with negligible amount of CO than the others due to the integration of CuO particles into the CeO2 lattice, as evidenced by XRD, and a interaction of Au and CuO species, as evidenced by TPR. A 50:50 Cu:Ce atomic ratio was optimal for Au supported on CuO–CeO2 catalysts which can then promote SRM. Increasing the reaction time, by reducing the liquid feed rate from 3 to 1.5 cm3 h?1, resulted in a catalytic activity with complete (100%) methanol conversion, and a H2 and CO selectivity of ~82% and ~1.3%, respectively. From stability testing, Au/(50:50)CuO–CeO2 catalysts were still active for 540 min use even though the CuO was reduced to metallic Cu, as evidenced by XRD. Therefore, it can be concluded that metallic Cu is one of active components of the catalysts for SRM. 相似文献
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Yuththaphan Phongboonchoo Nutthavich Thouchprasitchai Sangobtip Pongstabodee 《International Journal of Hydrogen Energy》2017,42(17):12220-12235
Catalytic activities of Ce–Mg promoted Cu/Al2O3 catalysts via methanol steam reforming was investigated in terms of the methanol conversion level, carbon monoxide selectivity and hydrogen yield. The factors chosen were the reaction temperature, copper content, Mg/(Ce + Mg) weight-percentage and steam to carbon ratios. The catalysts were prepared by co-precipitation and characterized by means of XRD, BET, H2-TPR, and FESEM. The Ce–Mg bi-promoter catalysts gave higher performance due to magnesium penetration into the cerium structure causing oxygen vacancy defects on the ceria. A response-surface-model was then designed to optimize the condition at a 95% confidence interval for complete methanol conversion to a high H2 yield with a low CO content, and revealed an optimal copper level of 46–50 wt%, Mg/(Ce + Mg) of 16.2–18.0%, temperature of 245–250 °C and S/C ratio of 1.74–1.80. No deactivation of the Cu0.5Ce0.25Mg0.05/Al catalyst was observed during a 72-h stability test. 相似文献
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