Nickel–Alumina Catalysts in the Reaction of Carbon Dioxide Re-Forming of Methane under Thermal and Microwave Heating

Abstract

The activity of 10% Ni/Al 2 O 3 and 10% Ni/Al 2 O 3 -F catalysts prepared by sol−gel method was studied in the carbon dioxide methane re-forming under thermal and microwave heating. It is found that replacement of thermal for microwave heating results in stable activity restoration with substantial suppression of coke formation. Thermodynamic calculation of reactants and products equilibrium concentrations in the main and side reactions, including soot formation, shows that in the microwave-activated process of carbon dioxide methane reforming on 10% Ni/Al 2 O 3 -F the reactions of carbon and perhaps methane steam reforming are significantly intensified. Physicochemical methods (DRIFT spectroscopy, adsorption measurements by the BET method) revealed differences in surface properties of catalysts (specific surface area, pore volume, acidity), as well as electronic state of nickel. The results obtained demonstrate the perspectives of the microwave activation of the reactions of carbon dioxide re-forming not only in the case of methane but also in the cases of ethane and propane, where the problem of coke formation and catalyst deactivation is even more significant.

Dry reforming of methane over Co–Mo/Al2O3 catalyst under low microwave power irradiation

“…Other researchers explored the catalytic performance with C (a good MW acceptor) or mixed C with more active catalysts such as Ni/Al 2 O 3 . [42][43][44] In these catalyst systems, the maximum conversions of CH 4 (>90%) and CO 2 (>80%) could be obtained at a temperature above 800°C. However, the decrease in the catalytic activity was rapidly observed in less than 1 or 2 h. The reason for such poor stability is due to the occurrence of the Boudouard reaction (eqn (3)), leading to C loss during the DRM process.…”

Analysis of CO2 utilization into synthesis gas based on solar thermochemical CH4-reforming

“…Cruz-Hernández [9] reported that syngas produced at the highest temperature was not produced by the CH 4 reforming, but by the CH 4 partial oxidation. However, the decrease in H 2 O would be attributed to carbon gasification into CO and H 2 since, at high temperatures (950 °C and above), H 2 O can react with a layer of coal to produce carbon CO and H 2 [52] . Besides, the gradual decrease in the conversion of CH 4 indicates that the activity of catalysts is significantly reduced by the formation of coke deposits on the surface of catalysts [51] .…”

Microwave-Assisted Dry and Bi-reforming of Methane over M–Mo/TiO2 (M = Co, Cu) Bimetallic Catalysts

“…MW heating is particularly attractive for methane reforming owing to its role to provide a much shorter reaction time relative to the conventional heating technique and specific effects to reactant molecules, which allow reforming reactions to occur at less demanding conditions (i.e., lower pressure and temperature) . MW heating also enhances the removal of deposited carbon from the catalyst surface to regenerate active sites due to the strong MW absorption of carbonaceous species to promote the Boudouard reaction . Several researchers have also explored the application of MW-induced plasma in noncatalyzed methane reforming reactions. − The drawback of such an MW-based plasma process, however, lies in the high input power required to stabilize the plasma production.…”

“…14 MW heating also enhances the removal of deposited carbon from the catalyst surface to regenerate active sites due to the strong MW absorption of carbonaceous species to promote the Boudouard reaction. 15 Several researchers have also explored the application of MW-induced plasma in noncatalyzed methane reforming reactions. 16−24 The drawback of such an MW-based plasma process, however, lies in the high input power required to stabilize the plasma production.…”