Highly Carbon-Resistant Y Doped NiO–ZrOm Catalysts for Dry Reforming of Methane

et al. 2021

Catalysts

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Copper and iron promoted ZrO2 catalysts were prepared by one-pot synthesis using urea. The studied catalysts were characterized by XRD, N2 physisorption, XPS, NH3-TPD, and tested in the selective catalytic reduction of NO with NH3 (NH3-SCR) in the absence and presence of water vapor under the experimental conditions representative of exhaust gases from stationary sources. The influence of SO2 on catalytic performance was also investigated. Among the studied catalysts, the Fe-Zr sample showed the most promising results in NH3-SCR, being active and highly selective to N2. The addition of SO2 markedly improved NO and NH3 conversions during NH3-SCR in the presence of H2O. The improvement in acidic surface properties is believed to be the cause.

Section: Surface Properties Of Zro 2 Supported Catalystsmentioning

confidence: 92%

Novel Preparation of Cu and Fe Zirconia Supported Catalysts for Selective Catalytic Reduction of NO with NH3

Świrk

et al. 2021

Catalysts

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“…The diffraction peaks at 44.5, 51.8, and 76.4 • corresponded to the Ni metal (PDF no. 04-0850) over reduced catalysts, as shown in Figure 7b, and there was no diffraction peak of NiO [57]. In addition, no obvious diffraction peak of Si species was detected on Ni-xSi/ZrO 2 catalysts, suggesting that Si was in a high dispersion or amorphous state [51].…”

Section: The Results Of Co 2 -Tpd On Ni-xsi/zro 2 Catalystsmentioning

confidence: 93%

The Effect of Si on CO2 Methanation over Ni-xSi/ZrO2 Catalysts at Low Temperature

Zhao

et al. 2021

Catalysts

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A series of Ni-xSi/ZrO2 (x = 0, 0.1, 0.5, 1 wt%, the controlled contents of Si) catalysts with a controlled nickel content of 10 wt% were prepared by the co-impregnation method with ZrO2 as support and Si as a promoter. The effect of different amounts of Si on the catalytic performance was investigated for CO2 methanation with the stoichiometric H2/CO2 molar ratio (4/1). The catalysts were characterized by BET, XRF, H2-TPR, H2-TPD, H2-chemisorption, CO2-TPD, XRD, TEM, XPS, and TG-DSC. It was found that adding the appropriate amount of Si could improve the catalytic performance of Ni/ZrO2 catalyst at a low reaction temperature (250 °C). Among all the catalysts studied, the Ni-0.1Si/ZrO2 catalyst showed the highest catalytic activity, with H2 and CO2 conversion of 73.4% and 72.5%, respectively and the yield of CH4 was 72.2%. Meanwhile, the catalyst showed high stability and no deactivation within a 10 h test. Adding the appropriate amount of Si could enhance the interaction between Ni and ZrO2, and increase the Ni dispersion, the amounts of active sites including surface Ni0, oxygen vacancies, and strong basic sites on the catalyst surface. These might be the reasons for the high activity and selectivity of the Ni-0.1Si/ZrO2 catalyst.

“…44 − 46 The third peak (γ) at 600–800 °C was assigned to the NiO species in the skeleton of ZrO 2 and ZrO 2 species. 47 , 48 The proportion of three peaks on NiO–10Al 2 O 3 –ZrO 2 and NiO–ZrO 2 catalysts is shown in Table 4 . The content of the β peak was about 40% on the NiO–10Al 2 O 3 –ZrO 2 catalyst, which was higher than the one on the NiO–ZrO 2 catalyst (15%) because the NiO–10Al 2 O 3 –ZrO 2 catalyst exhibited a large pore volume and pore diameter.…”

Section: Resultsmentioning

confidence: 99%

“… 54 , 55 The peaks at about 182.3, 181.4, 180.5, and 179.3 eV are attributed to the Zr 4+ , Zr 3+ , Zr 2+ , and Zr 1+ , respectively. 47 , 56 − 60 The proportion of Zr 4+ and Zr 3+ is listed at Table 5 . The proportion of surface Zr 4+ on NiO–ZrO 2 and NiO–10Al 2 O 3 –ZrO 2 catalysts were 11 and 14%, respectively, which indicated that a part of Zr 4+ could be reduced to Zr 3+ after reduction on both catalysts.…”

Section: Resultsmentioning

confidence: 99%

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Syngas Production via CO₂ Reforming of Methane over Aluminum-Promoted NiO–10Al₂O₃–ZrO₂ Catalyst

et al. 2021

ACS Omega

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CO 2 reforming of methane was studied at medium temperature (700 °C) using a GSHV of 48,000 h –1 over nickel catalysts supported on ZrO 2 promoted by alumina. The catalysts were prepared by a one-step synthesis method and characterized by BET, H 2 -TPR, XRD, XPS, TEM, Raman spectroscopy, and TGA. The NiO–10Al 2 O 3 –ZrO 2 catalyst exhibited higher catalytic performance in comparison with the NiO–ZrO 2 catalyst. The enhancement of catalytic activity in dry reforming could be associated with the alterations in surface properties due to Al promotion. First, the Al promoter could modify the structure of ZrO 2 , leading to an increase of its pore volume and pore diameter. Second, the NiO–10Al 2 O 3 –ZrO 2 catalyst exhibited high resistance to sintering. Third, the NiO–10Al 2 O 3 –ZrO 2 catalyst showed high suppression to the loss of nickel during a long-term catalytic test. Finally, the addition of Al could inhibit the reduction of ZrO 2 during the reduction and reaction, endowing further the stability.