Relationship between catalyst structure and activity in CO2 methanation of Ru-based catalysts: recent progress and future prospects

Abstract

The highly attractive reaction of CO₂ to methane (CH₄) not only recycles CO₂ emissions but also provides an efficient way to generate usable energy from renewable hydrogen. Over the past decade, there have been numerous reports on CO₂ methanation. While there have been discussions on catalytic materials for enhancing activity, the underlying structure–activity relationships are still not fully understood. Therefore, it is important to provide a thorough review that focuses on the correlation between the catalyst's structure and its effectiveness in CO₂ methanation. In this review, we first examine the choice of metals and supports based on the hydrogenation mechanism. Typically, different metal oxides and carbon materials are used in this reaction system, with ruthenium (Ru) metal being considered a promising active component. We then summarize the latest advancements in Ru-based catalysts, including the effects of composition and active metal size. Additionally, we delve into the composition and morphology of the support body in this reaction, providing a detailed understanding of surface groups, oxygen defects, and various dimensions of the support body's morphology. Furthermore, we also demonstrate the significance of metal–support interactions and promoters in the CO₂ methanation process. Additionally, we discuss the obstacles and potential future directions in this area, offering insights into future catalyst design.