Low Temperature Sabatier CO2 Methanation

Abstract

The CO₂ methanation reaction, or Sabatier reaction, is experiencing renewed interest in the context of large-scale recycling of point CO₂ emissions, leading to the power-to-gas technology. The reaction represents a flexible route to transform CO₂ into methane by hydrogenation with (green) dihydrogen. This exothermic transformation takes place at a reasonable rate at temperatures above 200 °C and is directed to the targeted product at low temperatures. The CO₂ methanation nevertheless remains kinetically limited due to the chemical stability of CO₂ and the high bond dissociation energy for C═O in CO₂. Therefore, the current urgent demand is for the development of catalysts and associated processes with superior activity for CO₂ activation at low temperatures. This critical review aims to overview the state of the art of this low-temperature technology using thermal, plasma and photo-assisted catalysis. We summarize research advances around low-temperature CO₂ methanation, focusing on catalyst formulations (metal, supports and promoters), reaction mechanisms and suitable activation processes. We discuss each of these critical aspects of the technology and identify the main challenges and opportunities for low temperature (≤200 °C) CO₂ methanation.