Dual Active Sites of Embedded Ni and Surface Frustrated Lewis Pairs on CeO ₂ (110) for Efficient Photocatalytic CO ₂ Methanation

Developing efficient catalysts to drive the Sabatier reaction under mild conditions remains a grand challenge. Here we present an “embedded dual active site” strategy that exploits the strong metal–support interaction (SMSI) on the CeO 2 (110) surface to stabilize Ni nanoparticles, effectively integrating frustrated Lewis pair (FLP, Ce 3+ –O 2– ) sites for photocatalytic CO 2 activation with adjacent Ni sites for hydrogenation. Compared to shallow Ni embedding on CeO 2 (111), Ni nanoparticles are embedded significantly deeper in the CeO 2 (110) lattice. Concurrently, surface analyses reveal that CeO 2 (110) more readily generates FLPs (Ce 3+ and oxygen vacancy pairs) than CeO 2 (111). The resultant Ni 10 /CeO 2 photocatalyst delivers a CH 4 production rate of 2402.6 μmol·g –1 ·h –1 under UV–visible light irradiation, far exceeding the performance of control catalysts constructed on CeO 2 (111). In situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) and density functional theory (DFT) calculations reveal a synergistic mechanism involving enhanced surface CO 2 adsorption (adsorption energy lowered to ∼ −1.2 eV), efficient photocarrier separation, and reduced kinetic barriers for reaction intermediates, greatly promoting CO 2 activation, and subsequent hydrogenation.