Embedded Ni nanoparticles in CeZrO2 as stable catalyst for dry reforming of methane

Abstract

Ni nanoparticles embedded in CeO2 (Ni@CeO2) and CeZrO2 (Ni@CeZrO2) were synthesized by sol-gel method and compared with a Ni/CeO2 prepared by support impregnation. The performance of the catalysts was investigated for dry reforming of methane reaction. In situ XRD, XANES and TEM showed that Ni embedded in CeO2 improved the resistance to sintering along the reduction at 800 o C. Doping ceria with zirconia inhibited the growth of Ni particles and increased the oxygen mobility. SEM, TEM, Raman spectroscopy and TGA of the used catalysts after dry reforming of methane showed that carbon formation rate was significantly reduced for the catalysts containing Ni nanoparticles embedded in ceria structure. Carbon deposits were not detected over Ni@CeZrO2 after 24 h of reaction. Therefore, the control of Ni particle size and the high oxygen mobility of Ni@CeZrO2 catalyst inhibited carbon deposition and favored the mechanism of carbon removal, promoting catalyst stability.

Highly active and stable Ni dispersed on mesoporous CeO2-Al2O3 catalysts for production of syngas by dry reforming of methane

“…However, the intensity of this line starts to decrease when the sample is heated at 200 °C and it is no longer observed after reduction at 800 °C. According to the literature [13,31], the reduction of ceria-based materials leads to the shift of the lines characteristic to CeO2 to lower angles due to the conversion of Ce 4+ to Ce 3+ species but the intensities of these lines do not change. Therefore, what is causing the disappearance of the CeO2 lines during reduction?…”

“…Therefore, the limitation of the Ni particle sintering process is crucial to prevent the carbon formation during the DRM at high temperature. The catalyst design enables the control of the metal particle size for instance by embedded the metal particle in the oxide matrix [13] or by generating porosity in which the metal particle can be confined [14].…”

“…The rate of carbon formation for the catalysts during DRM at 800 °C for 72 h of TOS are listed on Table 4. Ni/0Ce-AlO 800 °C, CH4:CO2 = 1:1 3.7 [33] Ni/05CeAlO 800 °C, CH4:CO2 = 1:1 2.8 [33] Ni/10CeAlO 800 °C, CH4:CO2 = 1:1 1.8 [33] Ni/15CeAlO 800 °C, CH4:CO2 = 1:1 1.2 [33] Ni/CeO2 800 °C, CH4:CO2 = 1:1 9.7 [13] Ni@CeO2 800 °C, CH4:CO2 = 1:1 1.6 [13] Ni@CeZrO2 800 °C, CH4:CO2 = 1:1 0.0 [13] LaNiO3 800 °C, CH4:CO2 = 1:1 27.0 [43] LaNiO3/SiCeO2 800 °C, CH4:CO2 = 1:1 0.3 [43] NiCu/Ce0.9Gd0.1O2 800 °C, CH4:CO2 = 1:1 12.2 [46] Ni/CeO2 800 °C, CH4:CO2 = 1:1 4.8 [47] Ni/CZ100 700 °C, CH4:CO2 = 1:1 0.4 [48] Ni/CZ75 700 °C, CH4:CO2 = 1:1 3.5 [48] Ni/CZ44 700 °C, CH4:CO2 = 1:1 1.7 [48] Ni/CZ28 700 °C, CH4:CO2 = 1:1 0.7 [48]…”

“…In this case, the metal is confined into support structure which inhibits metal sintering and suppress carbon deposition. Recently, our group have developed embedded-Ni catalyst in CeO2 and CeZrO2 supports which exhibited high resistance against Ni sintering, as well as an enhanced oxygen mobility due to the high interaction between Ni and the support, suppressing carbon formation [13].…”

Recent Progresses in the Design and Fabrication of Highly Efficient Ni-Based Catalysts With Advanced Catalytic Activity and Enhanced Anti-coke Performance Toward CO2 Reforming of Methane

“…As shown in Figure 16, the NAC-SG catalyst displayed much higher feed conversion, product yield, and H 2 /CO ratio than NAC-I catalyst. Marinho et al (2020) found the positive effect of the sol-gel method on the stabilization of Ni particle size in the reduction process at high temperature (800 • C) Ni@CeO 2 . Besides, the above catalysts prepared by the sol-gel method also generated more oxygen vacancies and stronger metal-support interaction with CeZrO 2 and Ni than the impregnated Ni/CeO 2 catalyst.…”