Sustainable Synthesis of a Highly Stable and Coke-Free Ni@CeO2 Catalyst for the Efficient Carbon Dioxide Reforming of Methane

Abstract

A facile and green synthetic strategy is developed in this paper for the construction of an efficient catalyst for the industrially important carbon dioxide reforming of methane, which is also named the dry reforming of methane (DRM). Through controlling the synthetic strategy and Ni content, a high-performance Ni@CeO2 catalyst was successfully fabricated. The catalyst showed superb efficiency for producing the syngas with high and stable conversions at prolonged operating conditions. Incorporating Ni during the ceria (CeO2) crystallization resulted in a more stable structure and smaller nanoparticle (NP) size with a more robust interaction with the support than loading Ni on CeO2 supports by the conventional impregnation method. The H2/CO ratio was almost 1.0, indicating the promising applicability of utilizing the obtained syngas for the Fischer–Tropsch process to produce worthy chemicals. No carbon deposits were observed over the as-synthesized catalyst after operating the DRM reaction for 50.0 h, even at a more coke-favoring temperature (700 ∘C). Owing to the superb resistance to coke and sintering, control of the size of the Ni-NPs, uniform dispersion of the active phase, and potent metal interaction with the support, the synthesized catalyst achieved a magnificent catalytic activity and durability during serving for the DRM reaction for extended operating periods.

Low-Temperature Plasma-Assisted Catalytic Dry Reforming of Methane over CeO2 Nanorod-Supported NiO Catalysts in a Dielectric Barrier Discharge Reactor

“…The conversion rates for plasma thermal synergy employing our shaped 15 wt % NiO/CeO 2 NR catalyst are higher compared to those of other catalysts tested in different plasma environments. When compared to experiments employing nearly equal feed ratios and different Ni-based catalysts such as Ni/γ-Al 2 O 3 in a DBD reactor, x -Ni/γ-Al 2 O 3 ( x = 5, 10, 20) in a corona discharge reactor, x -Ni/Al 2 O 3 ( x = 15, 30) in a rotating gliding spouted bed reactor, structural and textural modified CaO, and 15 wt % Ni/TiO 2 , higher conversion rates were achieved by our shaped 15 wt % NiO/CeO 2 NR catalyst. Although certain conversions are possible at temperatures as low as 150 °C, the plasma thermal synergy effect becomes the most effective between 300 and 500 °C.…”

“…30,31 This is because each Ni ion substitution in the CeO 2 lattice creates an oxygen vacancy with two electrons to make up for the charge difference between Ce 4+ and Ni 2+ , leading to the formation of Ce 3+ ions, which is a key factor that influences the catalytic performance of the DRM reaction. 8 Therefore, it is reasonable to conclude that 15 wt % NiO/CeO 2 NR contains more oxygen defects than 5 wt % NiO/CeO 2 NR. The XPS profiles of the O 1s given in Figure 5b,e strongly support this hypothesis.…”

“…In contrast, the peaks U° and V° are located at 895.2 and 876.7 eV, respectively, and correspond to Ce 3+ . It is noted that the peaks at 895.2 and 876.7 eV represent the concentration of the Ce 3+ state, which is more vital for the 15 wt % NiO/CeO 2 NR catalyst than for the 5 wt % NiO/CeO 2 NR catalyst. , This is because each Ni ion substitution in the CeO 2 lattice creates an oxygen vacancy with two electrons to make up for the charge difference between Ce 4+ and Ni 2+ , leading to the formation of Ce 3+ ions, which is a key factor that influences the catalytic performance of the DRM reaction . Therefore, it is reasonable to conclude that 15 wt % NiO/CeO 2 NR contains more oxygen defects than 5 wt % NiO/CeO 2 NR.…”

“…For the DRM reaction, the researcher conducted multiple experiments with Ni-based catalysts supported on metal oxides, including alumina (Al 2 O 3 ), silica (SiO 2 ), ceria (CeO 2 ), and zirconia (ZrO 2 ), or a mixture of two or more of these oxides . Among these supports, CeO 2 received the most attention due to its unique reduction properties, its oxygen storage and release capacity, and its strong metal–support interaction (SMSI).…”

Optimization of Ni-Based Catalysts for Dry Reforming of Methane via Alloy Design: A Review

“…The main reasons for the strike of the DRM reaction are catalyst carbon deposition, , sintering, − and sulfur poisoning, ,− and the first two are unavoidable in the DRM process . Catalyst sintering occurs when the cohesion energy of the metal is greater than the binding energy of the metal with support at a high DRM temperature. , Sintering accelerated carbon deposition because large metal clusters accelerated coke formation . Carbon deposition was usually the most important mechanism of deactivation of the DRM catalyst.…”