Nanoscale spatial distribution engineering of CuFe2O4/MgO interfaces for high-efficiency hydrogen production and CO2 capture

• Mechanochemical synthesis enables nanoscale spatial control, shortening CO₂ diffusion paths and boosting MgO/CuFe₂O₄ synergy. • 99.9 % hydrogen yield achieved at 340 °C via SEWGS over CM10. • 19.95 mmol·g −1 CO 2 uptake with 79.8 % MgO utilization efficiency, outperforming physical mixtures by 3 times. • MgO coverage weakens CO adsorption and enhances CO 2 chemisorption. CuFe 2 O 4 /MgO composite catalysts are promising materials for integrated hydrogen production and CO 2 capture in sorption-enhanced water gas shift (SEWGS) reactions. However, inhomogeneous distribution of active components often limits H 2 yield. In this study, a mechanochemical approach was developed to synthesize CuFe 2 O 4 /MgO catalysts with nanoscale-controlled spatial distribution of catalytic and CO 2 -adsorptive sites. It was found that the MgO:CuFe 2 O 4 molar ratio plays a critical role in determining CO conversion and CO 2 uptake performance. The optimal catalyst (molar ratio = 10) achieved 99.9 % H 2 purity and a CO 2 uptake capacity of 19.95 mmol·g −1 (on MgO basis), reaching 79.8 % of the theoretical maximum (25 mmol·g −1 ) and tripling the capacity of the physically mixed catalyst (6.47 mmol·g −1 ). This high performance is attributed to well-matched hydrogen production and decarbonation rates (0.041 min −1 and 0.045 min −1 , respectively) under SEWGS conditions (340 °C, 0.1 MPa). Combined characterization and computational studies reveal that modulating the molar ratio tailors the surface affinity for CO and CO 2 via interfacial bonding/antibonding interactions, which weakens CO adsorption while promoting CO 2 chemisorption. Notably, the electrons transferred for CO 2 adsorption on CuFe 2 O 4 -loaded Mg 4 O 4 nanoclusters exceeded that on pure Mg 4 O 4 by over 10 %, indicating facilitated CO 2 removal and enabling stable high-purity hydrogen production. This work provides an effective strategy for advancing scalable low-carbon hydrogen technology.