Kinetic Investigation of CO₂-CH₄Reaction over Ni/La₂O₃Catalyst using Photoacoustic Spectroscopy

Abstract

Ni/La 2 O 3 with a high dispersion was prepared by reduction of LaNiO 3 perovskite oxide to examine the catalytic activity for the CO 2 -CH 4 reaction. The Ni/La 2 O 3 catalyst was found to be highly active for the reaction. The ratios of H 2 /CO were measured in a flow of the reaction mixture containing CO 2 /CH 4 /Ar using an on-line gas chromatography system operated at 1 atm and found to be varied with temperature between 0.66 and 1 in the temperature range of 500-800 o C. A kinetic study of the catalytic reaction was performed in a static reactor at 40 Torr total pressure of CO 2 /CH 4 /N 2 by using a photoacoustic spectroscopy technique. The CO 2 photoacoustic signal varying with the concentration of CO 2 during the catalytic reaction was recorded as a function of time. o C under various partial pressures of CO 2 and CH 4 , the reaction orders were determined to be 0.43 with respect to CO 2 and 0.33 with respect to CH 4 . The kinetic results were compared with those reported previously and used to infer a reaction mechanism for the Ni/La 2 O 3 -catalyzed CO 2 -CH 4 reaction.

Kinetic study of methane reforming with carbon dioxide over NiCeMgAl bimodal pore catalyst

“…Comparison of data between Figures and indicates that the CH 4 consuming rate was more sensitive to CH 4 partial pressure than to CO 2 partial pressure. At a constant CO 2 partial pressure, the reforming rate increased fast with the increase in CH 4 partial pressure; while at a constant CH 4 partial pressure, the increase in CO 2 partial pressure cause a relative slow rise in the reforming rate, which is in conformity with the results on a Ni‐Co/Al‐Mg catalyst but contrasts with the observations on Ni/La 2 O 3 catalyst and Ni‐Cr‐Al metallic foam with Ru/Al 2 O 3 catalyst …”

“…Comparison of data between Figures 5 and 6 indicates that the CH 4 consuming rate was more sensitive to CH 4 partial pressure than to CO 2 partial pressure. At a constant CO 2 partial pressure, the reforming rate increased fast with the increase in CH 4 partial pressure; while at a constant CH 4 partial pressure, the increase in CO 2 partial pressure cause a relative slow rise in the reforming rate, which is in conformity with the results on a Ni-Co/Al-Mg catalyst 10 but contrasts with the observations on Ni/La 2 O 3 catalyst 24,27 and Ni-Cr-Al metallic foam with Ru/Al 2 O 3 catalyst. 28 Effect of products' partial pressure on reforming rate Figure 7 shows the DRM reaction rate in terms of CH 4 , CO 2 , CO, and H 2 with variation of H 2 partial pressure, at constant input partial pressures of CH 4 /CO 2 /CO 5 20/20/5 kPa with N 2 as balance and at the reaction temperature of 873 K. It is clear in Figure 7 that the increase of H 2 partial pressure has positive effect on the consumption of CO 2 but negative effects on the CH 4 consumption and H 2 formation, and neutral influence on the CO formation.…”

The effects of stoichiometry on the properties of exsolved Ni‐Fe alloy nanoparticles for dry methane reforming

“…In the case of supports for Ni, many are oxides that have been used, including CeO 2, 11 ZrO 2, 24 SiO 2, 25,26 Al 2 O 3, 27 La 2 O 3, 23,28‐30 and activated carbon 31 . A select group of mixed oxides used as smart or intelligent supports can promote the stability and activity of Ni for DRM 32‐41 . The exsolved nanoparticles are highly dispersed, and nucleation involves strong adherence to the oxide surface 33,42‐44 .…”

“…In the case of supports for Ni, many are oxides that have been used, including 31 A select group of mixed oxides used as smart or intelligent supports can promote the stability and activity of Ni for DRM. [32][33][34][35][36][37][38][39][40][41] The exsolved nanoparticles are highly dispersed, and nucleation involves strong adherence to the oxide surface. 33,[42][43][44] This improved metalsupport interaction has been coined as "socketed" with marked stability that is impervious to sintering and coke formation.…”

Mechanistic Study of Ni/CeO2‐catalyzed CO2/CH4 Reaction Using Flow and Static Methods

“…The CO 2 photoacoustic spectroscopy was employed to monitor the change in CO 2 concentration. As described in previous papers, the photoacoustic technique is suitable for the in situ monitoring of the CO 2 /CH 4 reaction because the photoacoustic signal is directly related to the CO 2 concentration in the reactor. The reactor was connected to a differential photoacoustic cell consisting of a reference cell and a sample cell separated by a ZnSe window.…”