CeO₂- and CaO-Promoted Precipitation Method for One-Step Preparation of Vermiculite-Based Multilayer Mesoporous Ni-Based Catalysts for Dry Reforming of Methane

Abstract

In this paper, a molecular sieve (VSiO 2 ) prepared from modified vermiculite is used as a support, and a multilayer mesoporous catalyst, Ni-VSiO 2 , is prepared while the active components are loaded in one step by the precipitation method. The catalyst is further modified by adding additives Ca and Ce to prepare the catalyst Ni-5x-VSiO 2 (x = Ce, Ca) and is used for the dry reforming of methane reaction. The catalyst is characterized by X-ray fluorescence, Brunauer−Emmett−Teller analysis, scanning electron microscopy, hydrogen temperature-programmed reduction test, transmission electron microscopy, thermogravimetric analysis, and other technical means. The result shows that under a normal pressure of 750 °C, the catalyst Ni-Ca-VSiO 2 has good stability. The catalyst Ni-Ce-VSiO 2 has good activity, stability and carbon deposition resistance, and the conversion rates of CO 2 and CH 4 are 88% and 78%, respectively. This is because the mesoporous structure allows Ni nanoparticles to enter the pores of the catalyst support, thereby inhibiting the aggregation of the active component Ni and improving its sintering resistance. CeO 2 additives provide more oxygen vacancies to inhibit the formation of carbon deposits. At the same time, the strong interaction between the active component Ni and the additive CeO 2 is also beneficial to improve its sintering resistance.

Effect of Calcination Temperature on Cu-Modified Ni Catalysts Supported on Mesocellular Silica for Methane Decomposition

“…4-0850), respectively. 14 , 42 , 43 The diffraction peaks of copper were not found in any catalysts because the crystallite size of copper could be below the detection limit of the XRD technique (<5 nm). The crystallite size of metallic nickel on the NiCu/MS catalysts was calculated using the Scherrer equation and the result is presented in Table 1 .…”

“…4-0850). 14 , 42 , 43 However, the diffraction peak of copper was not identified in the used catalysts because the copper metal was well dispersed on the catalyst surface.…”

“…47-1406), and the shoulders peak located at 2θ of 44.51° and 51.92° corresponded to the metallic nickel (JCPDS. 4-0850). ,, However, the diffraction peak of copper was not identified in the used catalysts because the copper metal was well dispersed on the catalyst surface.…”

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

“…[10] 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.…”

“…Vermiculite, as a material with a two‐dimensional layered model aluminosilicate and water molecular layer structure, has good binding force, cationicity, adsorption and swelling properties [10] . 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] .…”