Inducing efficient proton transfer through Fe/Ni@COF to promote amine-based solvent regeneration for achieving low-cost capture of CO2 from industrial flue gas

• Solid acid catalysts are designed to reduce to energy consumption for low-cost carbon capture from industrial flue gas. • Microstructure and chemical state of heterointerface is detailed by various measurements. • The created coordination of Ni(Fe)–N and Ni(Fe)–N–Ni(Fe) stimulates the production of Brønsted acid sites. • Ni/Fe@COF has an obvious promotion for solvent regeneration and CO 2 desorption. • The Ni/Fe atoms around heterointerface is the main active center for catalytic reaction. Catalytic amine-based solvent regeneration with solid acid is a feasible option for reducing energy consumption of CO 2 capture, but facing crucial challenges on designing material structures and understanding reaction mechanisms. Herein, we cover the nanoscale NiFe 2 O 4 cluster with covalent organic frameworks (COFs), to prepare solid acid catalysts. The pristine chemical bonds of Ni(Fe)-O and Ni(Fe)-Ni(Fe) are substituted by Ni(Fe)-N and Ni(Fe)-N-Ni(Fe) by targeting the anchoring of NiFe 2 O 4 cluster over COFs. The created coordination state stimulates the production of Brønsted acid sites. The obtained nanomaterials achieve a considerable improvement in CO 2 desorption of up to 290.1 mmol/(min·g) at 88 °C for spent monoethanolamine (MEA) solvent, representing a substantial increase of 540% relative to traditional thermal desorption. Consequently, the energy consumption of MEA generation is reduced by approximately 58%. Intermediate species (HCO 3− , CO 3 2− , and RNHCOO − ) and reaction pathways are established by combining operando Raman spectroscopy and ex situ 13 C NMR spectrum measurements. Theoretical calculations are performed to clarify the transformation mechanism of the acid sites around Ni/Fe atoms and its intrinsic role in the adsorption equilibrium of solvent regeneration.