Dry (CO2) reforming of methane (DRM) is a well-studied reaction that is of both scientific and industrial importance. This reaction produces syngas that can be used to produce a wide range of products, such as higher alkanes and oxygenates by means of Fischer–Tropsch synthesis. DRM is inevitably accompanied by deactivation due to carbon deposition. DRM is also a highly endothermic reaction and requires operating temperatures of 800–1000 °C to attain high equilibrium conversion of CH4 and CO2 to H2 and CO and to minimize the thermodynamic driving force for carbon deposition. The most widely used catalysts for DRM are based on Ni. However, many of these catalysts undergo severe deactivation due to carbon deposition. Noble metals have also been studied and are typically found to be much more resistant to carbon deposition than Ni catalysts, but are generally uneconomical. Noble metals can also be used to promote the Ni catalysts in order to increase their resistance to deactivation. In order to design catalysts that minimize deactivation, it is necessary to understand the elementary steps involved in the activation and conversion of CH4 and CO2. This review will cover DRM literature for catalysts based on Rh, Ru, Pt, and Pd metals. This includes the effect of these noble metals on the kinetics, mechanism and deactivation of these catalysts.

A review of dry (CO2) reforming of methane over noble metal catalysts

Although technological practice should minimize environmental impact, this is not always economically feasible. During the past decade, for example, there has been increasing global concern over th...

CO2 Reforming of CH4

Hydrogen production reactions from carbon feedstocks: fossil fuels and biomass.

Review on methanation – From fundamentals to current projects

http://iglesia.cchem.berkeley.edu/Publications/JournalofCatalysis_224_370_2004.pdf

Isotopic and kinetic assessment of the mechanism of reactions of CH4 with CO2 or H2O to form synthesis gas and carbon on nickel catalysts

Activation of CH4 and Its Reaction with CO2 over Supported Rh Catalysts

Methanation of CO2 on supported rhodium catalyst

The dissociation of CH4 and CO2, as well as the reaction between CH4 and CO2 at 723–823 K have been studied over alumina supported Pt metals. In the high temperature interaction of CH4 with catalyst surface small amounts of C2H6 were detected. In the reaction of CH4+CO2, CO and H2 were produced with different ratios. The specific activities of the catalysts decreased in the order: Ru, Pd, Rh, Pt and Ir, which agreed with their activity order towards the dissociation of CO2.

Catalytic reaction of CH4 with CO2 over alumina-supported Pt metals

The transformation of C in the form of CO2 into hydrocarbons was investigated on supported Ru catalysts. Special attention was paid to the surface processes occurring during the removal of the O atoms of CO2 by H2 and on the identification of surface species formed during the reaction. Infrared spectroscopic measurements revealed that chemisorbed CO and formate ion are formed during the coadsorption of H2+ CO2 at 373 K and also during the methanation of CO2 at higher temperatures. The CO formed produced a weak absorption band at lower frequencies (1990–2000 cm–1) than did the CO alone (2030–2040 cm–1). This shift was attributed to the effect of hydrogen adsorbed on the same Ru atoms and to that of surface C formed during the reaction. Evidence is presented to show that formate ion forms on the Ru but migrates rapidly onto the supports. It is considered as an inactive species in the methanation of CO2.The hydrogenation of CO2 on Ru/Al2O3 occurred at a measurable rate above 443 K yielding almost exclusively CH4. The formation of surface carbon was detected during the reaction at a level ca. 1.5 orders of magnitude less than in the H2+ CO reaction. The rate of CH4 formation is described by the expression NCH4= 2.7 × 106 exp (–16.1/RT)×PH2× 0.47 PCO2. It is proposed that the synthesis of CH4 from H2+ CO2 occurs via the formation of surface C and its subsequent hydrogenation.

A. Erdöhelyi

Papers

Activation of CH4 and Its Reaction with CO2 over Supported Rh Catalysts

Methanation of CO2 on supported rhodium catalyst

Catalytic reaction of CH4 with CO2 over alumina-supported Pt metals

Methanation of CO2 on supported Ru catalysts

Effects of the support on the adsorption and dissociation of CO and on the reactivity of surface carbon on Rh catalysts