Calcium-looping reforming of methane realizes in situ CO₂ utilization with improved energy efficiency.

Abstract

Closing the anthropogenic carbon cycle is one important strategy to combat climate change, and requires the chemistry to effectively combine CO₂ capture with its conversion. Here, we propose a novel in situ CO₂ utilization concept, calcium-looping reforming of methane, to realize the capture and conversion of CO₂ in one integrated chemical process. This process couples the calcium-looping CO₂ capture and the CH₄ dry reforming reactions in the CaO-Ni bifunctional sorbent-catalyst, where the CO₂ captured by CaO is reduced in situ by CH₄ to CO, a reaction catalyzed by catalyzed by the adjacent metallic Ni. The process coupling scheme exhibits excellent decarbonation kinetics by exploiting Le Chatelier's principle to shift reaction equilibrium through continuous conversion of CO₂, and results in an energy consumption 22% lower than that of conventional CH₄ dry reforming for CO₂ utilization. The proposed CO₂ utilization concept offers a promising option to recycle carbon directly at large CO₂ stationary sources in an energy-efficient manner.