Deactivation Mechanism and Anti-Deactivation Measures of Metal Catalyst in the Dry Reforming of Methane: A Review

Abstract

In recent decades, the massive emission of greenhouse gases, such as carbon dioxide and methane, into the atmosphere has had a serious impact on the ecological environment. The dry reforming of carbon dioxide and methane to syngas cannot only realize the resource utilization of methane and carbon dioxide but also reduce global climate change. It is of great significance in carbon emission reduction. Owing to the dry reforming of methane (DRM) being a strongly endothermic reaction, it needs to be carried out under high-temperature conditions. It makes the catalyst have problems of the sintering of metal, carbon deposition, and poisoning. This article revolves around the problem of catalyst deactivation during the DRM reaction. It expands upon the thermodynamics and mechanisms of the DRM reaction, analyzes the causes of metal catalyst deactivation due to carbon deposition, sintering, and poisoning, and summarizes how the active components, supports, and additives of metal catalysts restrain the DRM catalyst deactivation during the reaction. The analysis revealed that changing the type and size of the active metal, adjusting the properties of the support, and adding additives can further regulate the dispersion of the active component, the interaction between the active component and the support, the oxygen vacancies of the support, and the acidity and basicity of the catalyst surface, ultimately achieving control over the metal catalyst’s resistance to sintering, carbon deposition, and sulfur poisoning. In addition, it discusses the application of metal catalysts in photothermal and plasma-catalyzed DRM. Finally, it outlines the prospects for research on metal catalysts for the DRM.

Recent advances in promoting dry reforming of methane using nickel-based catalysts

“…31,32 The formed carbonaceous species would remain on the active sites surface and hinder the access of CO 2 and CH 4 to the inner unreacted active sites. 33,34 CO 2 is also likely to react with H 2 from the methane dissociation, according to the RWGS (eqn (4)), leading to a H 2 /CO ratio less than 1.0, 35,36 related to the equilibrium at temperature ranges. 29,35,37 To minimize the effect, high temperature for reaction and timely products removal is required.…”

“…5. According to the energy of carbonaceous species, three carbonaceous species can be distinguished: 61,62 (I) adsorbed atomic carbon (C α ), C α is a combination of *CH x fragments from CH 4 and CO 2 on the catalytic surface. 63 It is the highly active atom that can mostly react with CO 2 or be further gasified; 22 (II) filamentous carbon (C β ): C β is a type of low-activity carbon species and originates from the C α that reacts with water, carbon dioxide and hydrogen.…”

“…11). 61,71,130 In a conclusion, the effect of Fe can be attributed to the following: (a) slow down the coking rate and concomitantly accelerate the carbon gasification rate; (b) enable small nickel size to change the carbon species to a type easily oxidized; (c) increase the oxyphilic property of the material.…”

Study on the Deactivation Mechanism of Ru/C Catalysts

“…Research on the potential mechanisms of deactivation in supported catalysts has received considerable attention [36][37][38][39][40]. It primarily stems from changes in the catalyst's physical structure, active components, and auxiliary components due to chemical reactions or phase transitions [41][42][43][44][45][46]. The China Institute of Atomic Energy has developed a process utilizing small organic molecules as reducing agents.…”

Dry Reforming of Methane over 5%Ni/Ce1-xTixO2 Catalysts Obtained via Synthesis in Supercritical Isopropanol

“…The use of oxides with a high oxygen storage capacity (OSC) in addition to oxygen mobility as supports should prevent catalyst deactivation due to carbon formation, since the support oxygen is involved in the process of coke precursor gasification [4,22]. DRM over catalysts with high oxygen mobility includes the following stages: decomposition of CH 4 on supported Ni particles with the formation of H 2 and CH x fragments, activation of CO 2 on oxygen vacancies in the oxide support with the formation of CO and active lattice oxygen, diffusion of active oxygen from the support to metal particles followed by oxidation of CH x fragments [12,23,24].…”