scholarly journals The Effects of CeO2 and Co Doping on the Properties and the Performance of the Ni/Al2O3-MgO Catalyst for the Combined Steam and CO2 Reforming of Methane Using Ultra-Low Steam to Carbon Ratio

Catalysts ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 1450
Author(s):  
Nichthima Dharmasaroja ◽  
Tanakorn Ratana ◽  
Sabaithip Tungkamani ◽  
Thana Sornchamni ◽  
David S. A. Simakov ◽  
...  
Keyword(s):  
Catalytic Performance ◽  
Dissociative Adsorption ◽  
Impregnation Method ◽  
Oxygen Species ◽  
Temperature Programmed Reduction ◽  
Co2 Reforming ◽  
Co Doping ◽  
Co2 Reforming Of Methane ◽  
Water Activation ◽  
Temperature Programmed

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.

scholarly journals Characteristics and activity of Ni/CeO2 catalyst modified by Cr2O3 in combined steam and CO2 reforming of CH4

2021 ◽  
Vol 10 (1) ◽  
pp. 104-108
Author(s):  
Phuong Phan Hong ◽  
Anh Nguyen Phung ◽  
Huy Tran Anh ◽  
Tri Nguyen ◽  
Loc Luu Cam
Keyword(s):  
Chemical Properties ◽  
Catalytic Performance ◽  
Molar Ratio ◽  
Impregnation Method ◽  
Co2 Reforming ◽  
X Ray ◽  
Co2 Reforming Of Ch4 ◽  
Transmission Electron ◽  
Physico Chemical ◽  
Temperature Programmed

A series of 10%wtNiO/CeO2-nanorod catalyst without and with Cr2O3 additive was prepared by simultaneous impregnation method. Several techniques, including N2 physisorption measurements, X-ray powder diffraction (XRD), temperature-programmed reduction using H2 (H2-TPR), CO2 temperature-programmed desorption (CO2-TPD), scanning electron microscope (SEM) and transmission electron microscopy (TEM) were used to investigate catalysts’ physico-chemical properties. The activity of the catalysts in combined steam and CO2 reforming of CH4 (BRM) was investigated at temperature range of 550-800 °C. The results showed that 10%NiO0.1%Cr2O3/CeO2 catalyst had the best catalytic performance due to a better reducibility and basicity. At 700 °C and CH4:CO2:H2O molar ratio in feed stream of 3:1.2:2.4, both conversion of CH4 and CO2 on this catalyst reached 98.5%.

scholarly journals CO2 reforming of CH4 over M(Ca, Ba, Sr)xLa1-xNiO3 perovskites used as coke resistant catalyst precursor

2020 ◽  
pp. 40-40
Author(s):  
Ana Carolina Trevisani Souza ◽  
Marcelo da Silva Batista
Keyword(s):  
Catalytic Performance ◽  
Partial Substitution ◽  
High Catalytic Activity ◽  
Catalyst Precursor ◽  
Co2 Reforming ◽  
Temperature Programmed Oxidation ◽  
Co2 Reforming Of Ch4 ◽  
Co2 Reforming Of Methane ◽  
Temperature Programmed ◽  
Carbon Dioxide Co2

Methane (CH4) and carbon dioxide (CO2) are greenhouse gases that have been converted into synthesis gas for the production of oxygenated chemicals and hydrocarbons. In this paper, M(Ca, Ba, Sr)xLa1-xNiO3 (x=0.0, 0.3 and 0.5) doped perovskites were successfully synthesized as catalyst precursors aiming at high catalytic activity and stability in the CO2 reforming of methane. These perovskites were characterized by X-ray diffraction (XRD), temperature programmed reduction by H2 (H2-TPR) and O2-temperature programmed oxidation (TPO). Its activity and carbon suppression were investigated in the CO2 reforming of methane. Results showed formation of perovskite structure, but La2NiO4 spinel and NiO were also detected in doped perovskites. The Ca, Ba and Sr partial substitution has evident influence on the reduction behavior of perovskites. All the doped perovskites used as catalyst precursors had better catalytic performance than LaNiO3. However, increasing the doping content decreased activity. Among doped perovskites, Ca0.3La0.7NiO3 showed better catalytic performance for the methane reforming reaction.

scholarly journals Nanosheet-Like Ho2O3 and Sr-Ho2O3 Catalysts for Oxidative Coupling of Methane

Catalysts ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 388
Author(s):  
Yuqiao Fan ◽  
Changxi Miao ◽  
Yinghong Yue ◽  
Weiming Hua ◽  
Zi Gao
Keyword(s):  
Oxidative Coupling ◽  
Temperature Programmed Desorption ◽  
Oxidative Coupling Of Methane ◽  
Molar Ratio ◽  
Impregnation Method ◽  
Oxygen Species ◽  
N2 Adsorption ◽  
Basic Sites ◽  
Chemisorbed Oxygen ◽  
Temperature Programmed

In this work, Ho2O3 nanosheets were synthesized by a hydrothermal method. A series of Sr-modified Ho2O3 nanosheets (Sr-Ho2O3-NS) with a Sr/Ho molar ratio between 0.02 and 0.06 were prepared via an impregnation method. These catalysts were characterized by several techniques such as XRD, N2 adsorption, SEM, TEM, XPS, O2-TPD (temperature-programmed desorption), and CO2-TPD, and they were studied with respect to their performances in the oxidative coupling of methane (OCM). In contrast to Ho2O3 nanoparticles, Ho2O3 nanosheets display greater CH4 conversion and C2-C3 selectivity, which could be related to the preferentially exposed (222) facet on the surface of the latter catalyst. The incorporation of small amounts of Sr into Ho2O3 nanosheets leads to a higher ratio of (O− + O2−)/O2− as well as an enhanced amount of chemisorbed oxygen species and moderate basic sites, which in turn improves the OCM performance. The optimal catalytic behavior is achievable on the 0.04Sr-Ho2O3-NS catalyst with a Sr/Ho molar ratio of 0.04, which gives a 24.0% conversion of CH4 with 56.7% selectivity to C2-C3 at 650 °C. The C2-C3 yield is well correlated with the amount of moderate basic sites present on the catalysts.

scholarly journals Novel Nickel- and Magnesium-Modified Cenospheres as Catalysts for Dry Reforming of Methane at Moderate Temperatures

Catalysts ◽  
2019 ◽  
Vol 9 (12) ◽  
pp. 1066 ◽  
Author(s):  
Bogdan Samojeden ◽  
Marta Kamienowska ◽  
Armando Izquierdo Colorado ◽  
Maria Elena Galvez ◽  
Ilona Kolebuk ◽  
...  
Keyword(s):  
Supported Catalysts ◽  
Temperature Programmed Desorption ◽  
Catalytic Performance ◽  
Dry Reforming ◽  
Dry Reforming Of Methane ◽  
Temperature Programmed Reduction ◽  
Fly Ashes ◽  
Coal Fly Ashes ◽  
Temperature Programmed ◽  
Mg Content

Cenospheres from coal fly ashes were used as support in the preparation of Ni–Mg catalysts for dry reforming of methane. These materials were characterized by means of XRD, H2-temperature-programmed reduction (H2-TPR), CO2-temperature-programmed desorption (CO2-TPD), and low-temperature nitrogen sorption techniques. The cenosphere-supported catalysts showed relatively high activity and good stability in the dry reforming of methane (DRM) at 700 °C. The catalytic performance of modified cenospheres was found to depend on both Ni and Mg content. The highest activity at 750 °C and 1 atm was observed for the catalyst containing 30 wt % Mg and 10, 20, and 30 wt % Ni, yielding to CO2 and CH4 conversions of around 95%.

scholarly journals Influence of Sulfur-Containing Sodium Salt Poisoned V2O5–WO3/TiO2 Catalysts on SO2–SO3 Conversion and NO Removal

Catalysts ◽  
2018 ◽  
Vol 8 (11) ◽  
pp. 541 ◽  
Author(s):  
Haiping Xiao ◽  
Chaozong Dou ◽  
Hao Shi ◽  
Jinlin Ge ◽  
Li Cai
Keyword(s):  
Photoelectron Spectroscopy ◽  
No Reduction ◽  
Catalytic Performance ◽  
Acid Sites ◽  
Impregnation Method ◽  
So2 Oxidation ◽  
Sodium Salts ◽  
X Ray ◽  
Temperature Programmed ◽  
Physical Features

A series of poisoned catalysts with various forms and contents of sodium salts (Na2SO4 and Na2S2O7) were prepared using the wet impregnation method. The influence of sodium salts poisoned catalysts on SO2 oxidation and NO reduction was investigated. The chemical and physical features of the catalysts were characterized via NH3-temperature programmed desorption (NH3-TPD), H2-temperature programmed reduction (H2-TPR), X-ray photoelectron spectroscopy (XPS), Brunauer–Emmett–Teller (BET), X-ray diffraction (XRD), and Fourier Transform Infrared Spectroscopy (FT-IR). The results showed that sodium salts poisoned catalysts led to a decrease in the denitration efficiency. The 3.6% Na2SO4 poisoned catalyst was the most severely deactivated with denitration efficiency of only 50.97% at 350 °C. The introduction of SO42− and S2O72− created new Brønsted acid sites, which facilitated the adsorption of NH3 and NO reduction. The sodium salts poisoned catalysts significantly increased the conversion of SO2–SO3. 3.6%Na2S2O7 poisoned catalyst had the strongest effect on SO2 oxidation and the catalyst achieved a maximum SO2–SO3-conversion of 1.44% at 410 °C. Characterization results showed sodium salts poisoned catalysts consumed the active ingredient and lowered the V4+/V5+ ratio, which suppressed catalytic performance. However, they increased the content of chemically adsorbed oxygen and the strength of V5+=O bonds, which promoted SO2 oxidation.

Preparation and Characterization of the Typical Pt-NSR Catalyst

2011 ◽  
Vol 412 ◽  
pp. 365-369
Author(s):  
Yuan Feng Huang ◽  
Wei Jun Zhang ◽  
Li Shen ◽  
Jin Hu ◽  
Zhuo Heng Li ◽  
...  
Keyword(s):  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Performance Testing ◽  
High Specific Surface Area ◽  
Impregnation Method ◽  
Temperature Programmed Reduction ◽  
Temperature Programmed ◽  
Co Precipitation

A series of Ba-Al-O NSR supports and Pt/Ba-Al-O NSR catalysts are prepared by co-precipitation and impregnation method in this work. The catalyst and the support are characterized by XRD, SEM, SBET performance testing. The structure and texture of the supports is observed and discussed. The results of SBET indicate that the supports possess relative high specific surface area (94~110 m2/g). Temperature programmed reduction is characterized by means of H2-TPR.

Oxygen Radicals Occlusion/Release Behavior of Nanoporous Aluminosilicate, Ca12Al14-XSiXO33+0.5X (0≦X≦4)

2006 ◽  
Vol 45 ◽  
pp. 2105-2109
Author(s):  
Makoto Nagashima ◽  
Daisuke Hirabayashi ◽  
Kenzi Suzuki
Keyword(s):  
Catalytic Activity ◽  
Oxygen Content ◽  
Oxygen Radicals ◽  
Catalytic Performance ◽  
Oxygen Release ◽  
Release Behavior ◽  
Temperature Programmed Reduction ◽  
Temperature Programmed Oxidation ◽  
Temperature Range ◽  
Temperature Programmed

Oxygen radicals occlusion / release behavior of nanoporous aluminosilicate, Ca12Al14-XSiXO33+0.5X (0≦X≦4), synthesized under different condition was examined by the temperature programmed reduction (TPR) in an atmosphere of hydrogen in the temperature range of 200-1000°C and temperature programmed oxidation (TPO) measurement at 800°C. From the TPR results of Ca12Al14O33 (X=0) and Ca12Al10Si4O35 (X=4), it was found that there were three oxygen release peaks, denoted as α, β and γ, on each sample and the peaks appeared in the temperature range 300-420°C, 420-600°C, and 600-750°C, respectively. The oxygen contents of α and γ of samples were almost the same. However, the oxygen content of β in the sample with x = 4 was much larger, almost double, compared to that in x = 0. From the TPR, TPO results and catalytic performance, it was concluded that the oxygen content of β peak strongly influenced the catalytic activity of the nanoporous aluminosilicate in the propylene combustion.

Promotion Effects of La2O3 on Ni/Al2O3 Catalysts for CO2 Methanation

2015 ◽  
Vol 1118 ◽  
pp. 205-210 ◽  
Author(s):  
Wei Chang Chen ◽  
Wen Yang ◽  
Jian Dong Xing ◽  
Lei Liu ◽  
Hong Li Sun ◽  
...  
Keyword(s):  
Particle Size ◽  
Impregnation Method ◽  
Temperature Programmed Reduction ◽  
Active Components ◽  
X Ray ◽  
Induce Effect ◽  
Temperature Programmed ◽  
Ni Species ◽  
Adsorption Desorption ◽  
Catalytic Performances

Ni/Al2O3catalysts improved with different La contents were prepared by the conventional co-impregnation method and characterized by X-ray powder diffraction (XRD), N2adsorption-desorption, H2temperature-programmed reduction (H2-TPR). Catalytic performances for CO2methanation under condition (CO2/H2=4.1:1, 1 atm) were discussed in detail. XRD result demonstrated that the addition of La was in favor of decreasing the Ni particle size and increasing the dispersion of Ni species. The H2-TPR showed that La can change the proportion of various Ni species and increase the content of easily reducible Ni species. These results indicate that La species induce effect, resulting in smaller particle size and weaker interaction between active components and the support, higher dispersions, and reducibility of active phases, ultimately improving catalytic activity of CO2methanation.

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