Dual Active Sites of Embedded Ni and Surface Frustrated Lewis Pairs on CeO₂(110) for Efficient Photocatalytic CO₂ Methanation.

Abstract

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 CeO₂(110) surface to stabilize Ni nanoparticles, effectively integrating frustrated Lewis pair (FLP, Ce³⁺-O^2-) sites for photocatalytic CO₂ activation with adjacent Ni sites for hydrogenation. Compared to shallow Ni embedding on CeO₂(111), Ni nanoparticles are embedded significantly deeper in the CeO₂(110) lattice. Concurrently, surface analyses reveal that CeO₂(110) more readily generates FLPs (Ce³⁺ and oxygen vacancy pairs) than CeO₂(111). The resultant Ni₁₀/CeO₂ photocatalyst delivers a CH₄ production rate of 2402.6 μmol·g^-1·h^-1 under UV-visible light irradiation, far exceeding the performance of control catalysts constructed on CeO₂(111). In situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) and density functional theory (DFT) calculations reveal a synergistic mechanism involving enhanced surface CO₂ adsorption (adsorption energy lowered to ∼ -1.2 eV), efficient photocarrier separation, and reduced kinetic barriers for reaction intermediates, greatly promoting CO₂ activation, and subsequent hydrogenation.