Coupling lattice distortion with electronic states in highly crystalline LDHs for efficient piezocatalytic conversion of low-concentration CO2.

Abstract

The restricted conversion of low-concentration CO₂ in industrial flue gas and the structural degradation inherent in traditional defect engineering remain key challenges in piezocatalysis. In this work, highly crystalline Co-substituted MgAl-LDH nanosheets were constructed via isomorphous substitution. The atomic-level incorporation breaks the structural centrosymmetry through local lattice distortion. Consequently, it bolsters the piezoelectric built-in electric field to accelerate charge carrier separation. Simultaneously, the Co active sites optimize the interfacial d-band center, strengthen the specific adsorption of CO₂, and substantially lower the energy barrier for the rate-determining step (^⁎COOH formation). The strong coupling between the polarization-induced electric field and interfacial reaction kinetics lets 5% Co-MgAl-LDH outperform pristine MgAl-LDH by roughly 5.7-fold. At 25 °C under a 10% CO₂ atmosphere, 5%Co-MgAl-LDH achieves CO and H₂ production rates of 5542.8 and 3266.2 μmol g^-1 h^-1, respectively, corresponding to a CO/H₂ molar ratio of approximately 1.7:1. Together, local lattice distortion and interfacial electronic-state modulation account for this performance within an otherwise highly crystalline framework, pointing to a workable route for catalysts aimed at low-concentration CO₂ conversion.