CO₂ Capture and Direct Air CO₂ Capture Followed by Integrated Conversion to Methane Assisted by Metal Hydroxides and a Ru/Al₂O₃ Catalyst

Abstract

Abstract Rising CO 2 levels are leading to an increase in atmospheric greenhouse gas effect. Hydroxide salts have previously been shown to be promising reagents for capturing CO 2 . Utilizing a 5 %Ru/Al 2 O 3 catalyst, the carbonates obtained through CO 2 capture can then be hydrogenated to methane. This conversion occurs at relatively mild temperatures from 200 °C to 250 °C under 40 to 70 bar H 2 with yields of up to 100 %. Natural sources of calcium carbonate, like eggshells and seashells, can also be partially converted to methane. The direct air CO 2 capture and conversion of CO 2 to methane was achieved as well in quantitative yields.