CeO₂‐Based Frustrated Lewis Pairs via Defective Engineering: Formation Theory, Site Characterization, and Small Molecule Activation

Abstract

Activation of small molecules is considered to be a central concern in the theoretical investigation of environment‐ and energy‐related catalytic conversions. Sub‐nanostructured frustrated Lewis pairs (FLPs) have been an emerging research hotspot in recent years due to their advantages in small molecule activation. Although the progress of catalytic applications of FLPs is increasingly reported, the fundamental theories related to the structural formation, site regulation, and catalytic mechanism of FLPs have not yet been fully developed. Given this, it is attempted to demonstrate the underlying theory of FLPs formation, corresponding regulation methods, and its activation mechanism on small molecules using CeO2 as the representative metal oxide. Specifically, this paper presents three fundamental principles for constructing FLPs on CeO2 surfaces, and feasible engineering methods for the regulation of FLPs sites are presented. Furthermore, cases where typical small molecules (e.g., hydrogen, carbon dioxide, methane oxygen, etc.) are activated over FLPs are analyzed. Meanwhile, corresponding future challenges for the development of FLPs‐centered theory are presented. The insights presented in this paper may contribute to the theories of FLPs, which can potentially provide inspiration for the development of broader environment‐ and energy‐related catalysis involving small molecule activation.

Formal Decarbonylation of 1,2-Diketones Enabled by Synergistic Catalysis of Lewis Acid–Base Pairs and Redox Properties in CeO2

“…In contrast, Nb 2 O 5 (with stronger acidic sites than CeO 2 ) did not catalyze the benzilic-acid rearrangement step. These results and the fact that metal oxides with Lewis acid and base sites reported to act as CLPs did not induce the rearrangement step show that the exceptional catalytic performance of CeO 2 is possibly due to the concerted activation of diaryl 1,2-diketones by the unique Lewis acid–base pairs composed of lattice oxygen as the Lewis base and Ce 3+ and/or Ce 4+ as the Lewis acid, such as solid frustrated Lewis pairs (FLPs). − …”

Enhancing DMC Production from CO2: Tuning Oxygen Vacancies and In Situ Water Removal

“…Additionally, studies have shown oxygen vacancies serve as Lewis acid centers, enabling CO 2 hydrogenation reactions [23]. Lewis acid sites are often associated with oxygen vacancies and are commonly found in metal oxides, such as In 2 O 3 and CeO 2 [24]. Lewis acid sites are coordinatively unsaturated metal cations, and adjacent unobstructed lattice oxygen serves as a Lewis basic site.…”