Recent advances in dual functional calcium looping for integrated CO2 capture and conversion: a review

Abstract

Dual-functional calcium looping (CaL) is crucial for integrating CO₂ capture and conversion (ICCC), relying on efficient and cost-effective cyclic processes. Moreover, as energy fuels undergo continuous decarbonization and renewables are integrated into industrial and power generation sectors, there are concerted efforts to develop CaL-based ICCC processes that embody the true hybridization of decarbonization and energy saving. This review addresses the cutting edge of CaL-based ICCC technology, outlining strategies to overcome current limitations and suggesting future research directions aimed at reducing energy penalties through integrated multiscale approaches across materials, reactors, and systems. To this end, dual-functional Ca-based materials, covering composition, synthesis, and molding techniques, are investigated and the challenges in enhancing adsorption and catalytic stability are first discussed. Subsequently, the use of these materials in fixed-bed and fluidized-bed reactors is studied to optimize operating conditions, and their integration with renewable energy and other industrial processes is summarized. Finally, the research highlights the challenges and opportunities in the multiscale process intensification of CaL-based ICCC. It identifies gaps and outlines pathways to integrate renewable energy into our understanding of multiscale processes governing the dual-function stability of materials, reactor kinetic optimization, and system performance enhancement.