The Effect of Different Promoters (La₂O₃, CeO₂, and ZrO₂) on the Catalytic Activity of the Modified Vermiculite-Based Bimetallic NiCu/EXVTM-SiO₂ Catalyst in Methane Dry Reforming

Abstract

An X-NiCu/EXVTM-SiO2 (X = La, Ce, and Zr) catalyst was successfully prepared by using modified vermiculite as a support by the impregnation method. This experiment investigated the effects of La2O3, CeO2, and ZrO2 promoters on the activity of the NiCu/EXVTM-SiO2 catalyst. The study found that the addition of three different metal oxides did not improve the activity of the NiCu/EXVTM-SiO2 catalyst. On the contrary, some Ni active sites were covered by the promoter, which reduced the number of active sites, resulting in its catalytic activity lower than NiCu/EXVTM-SiO2. In addition, the promoted catalysts that were repeatedly calcined two times can significantly reduce the textural property as well as active sites of the catalyst, resulting in the lower activity. However, in X-NiCu/EXVTM-SiO2, Ce-NiCu/EXVTM-SiO2 showed relatively high initial catalytic activity, with the initial conversion rate of CH4 reaching 60.1% and the initial conversion rate of CO2 reaching 89.1%. This is mainly because the catalyst has a stronger basic site on the surface to facilitate the adsorption of CO2 molecules, and the smaller metal particle size is also conducive to the cleavage of C–H bonds.

One-Step Ethanol Conversion for 1,3-Butadiene Synthesis over Two-Dimensional VMT-SiO2 Nanomesh Loaded with Magnesium and Copper Oxide

“…In the meantime, they further prepared the bimetallic catalyst Ni-M/EXVTM-SiO 2 (M = Co, Cu, Fe) and confirmed that this Ni-Cu/EXVTM-SiO 2 catalyst displayed the best catalytic activity and stability. This is attributed to the better interaction and dispersion of the active components of the formed bimetallic Ni-Cu alloy, enhancing its ability to break C-H bonds [6]. Lu et al prepared various vermiculites supported on Ni catalysts via a plasma radiation treatment and found that the catalyst had high catalytic activity for CO methanation even at a very small Ni loading of 0.5 wt% [7].…”

Preparation of Vermiculite‐based Molecular Sieve‐Supported Ni‐Co Alloy Catalyst Assisted by Oleic Acid and Application in Dry Reforming of Methane

“…[11] Compared with the traditional thermal expansion method, the microwave-assisted preparation of the catalyst not only shortens the preparation time of the catalyst, but also improves the stability of the catalyst. [12] Therefore, the modified vermiculite technique has gradually entered the horizon of researchers. Several scholars have used acid treatment to prepare vermiculite-based molecular sieve support with two-dimensional microporous nanolayers, which have excellent properties such as large specific surface area.…”

“…Due to the small layer spacing of vermiculite molecular sieve, which is not conducive to gas diffusion, some scholars use microwave to obtain expanded vermiculite to prepare catalyst support [11] . Compared with the traditional thermal expansion method, the microwave‐assisted preparation of the catalyst not only shortens the preparation time of the catalyst, but also improves the stability of the catalyst [12] . Therefore, the modified vermiculite technique has gradually entered the horizon of researchers.…”

Investigação teórica da distribuição de espécies químicas e formação de vacâncias de oxigênio em >i<nanoclusters>/i< de óxidos mistos La>sub<2>/sub<Ce>sub<2>/sub<O>sub<7>/su

“…1,2 Sendo assim, uma possibilidade é pensar na utilização do metano de forma a evitar a simples queima como combustível. 3 A conversão de metano em produtos de maior valor agregado (etileno e hidrocarbonetos de maior massa molar) fornece outra via para utilização desse gás. 4 Existem dois desafios no densenvolvimento de catalisadores para essa reação: (i) A ligação C -H é muito estável.…”

“…O comportamento catalítico de óxidos La 2 Ce 2 O 7 , CeO 2 e La 2 O 3 têm sido estudado na literatura, 3 entretando, as propriedades, em regime nano, são pouco compreendidas. Estudos teóricos demonstraram que abaixo da temperatura de transição de fase, a temperatura tem pouca influência na morfologia de nanopartículas, que por sua vez é mais influenciada pela composição.…”