Sulphur poisoning and regeneration of Li-Ru/Al2O3 dual function material for the integrated CO2 capture and methanation

Effective integration of the CO2 capture from flue gases and its subsequent methanation with renewable H2 to achieve a net-zero chemical looping process poses strong challenges in the development of highly performing Dual Function Materials (DFMs). Li-Ru/Al2O3 DFM has been shown to optimally operate the cyclic process at low temperature (260 - 280 oC) with stable performance upon ageing and outstanding tolerance to SOx impurities in the flue gas, which, however, slowly deteriorate its CO2 capture capacity. This work investigates the mechanisms behind the sulfur-poisoning and self-regeneration capability of the catalytic features of the Li-Ru DFM as well as the irreversible inhibition of CO2 adsorption. Eventually, we demonstrate the remarkable effectiveness of a simple ex-situ regeneration procedure for a heavily sulfur-aged DFM aiming to minimize the consumption of critical raw materials within a circular economy approach.