Complexed Semiconductor Cores Activate Hexaniobate Ligands as Nucleophilic Sites for Solar‐Light Reduction of CO₂ by Water

Abstract

Although pure and functionalized solid-state polyniobates such as layered perovskites and niobate nanosheets are photocatalysts for renewable-energy processes, analogous reactions by molecular polyoxoniobate cluster-anions are nearly absent from the literature. We now report that under simulated solar light, hexaniobate cluster-anion encapsulated 30-Ni II -ion "fragments" of surface-protonated cubic-phase-like NiO cores activate the hexaniobate ligands towards CO 2 reduction by water. Photoexcitation of the NiO cores promotes charge-transfer reduction of Nb V to Nb IV , increasing electron density at bridging oxo atoms of Nbμ-O-Nb linkages that bind and convert CO 2 to CO. Photogenerated NiO "holes" simultaneously oxidize water to dioxygen. The findings point to molecular complexation of suitable semiconductor "fragments" as a general method for utilizing electron-dense polyoxoniobate anions as nucleophilic photocatalysts for solarlight driven activation and reduction of small molecules.

Metal-oxide clusters with semiconductive heterojunction counterparts

“…In 2022, the Weinstock group reported [Ni30(OH)24(H2O)8(Nb6O19)10] 44− (denoted as {Ni30Nb60}), a novel {Nb6} cluster-anion-encapsulated 30-Ni II -ion "fragments" of surface-protonated cubic-phase-like NiO. 69 It was prepared by adding NiCl2 to a basic solution of {Nb6} under ambient conditions, followed by a hydrothermal reaction at 170 °C. The {Ni30} core is a structurally and electronically analogous fragment of surface-protonated cubic-phase NiO.…”

Extraordinary Catalytic Performance of Nickel Half‐Metal Clusters for Light‐Driven Dry Reforming of Methane

“…Recently, an approach of light‐driven catalytic (photothermocatalytic) CO 2 reduction with CH 4 , [ 2–6,27–46 ] H 2 O, [ 47–52 ] and H 2 [ 53–61 ] using inexhaustible solar energy has been developed. It is very promising as it well integrates the low energy consumption of photocatalysis with the high catalytic efficiency of thermocatalysis.…”

Ce-Mediated Molecular Tailoring on an Unprecedented Gigantic Polyoxometalate {Mo132} into Half-Closed Product {Ce11Mo96} for Achieving High Proton Conduction

“…[1][2][3] Recently, targeted design and synthesis of POM clusters have aroused much concern to explore the basic principles of structure and bonding as well as to expand the functionalities of POM-based materials and devices. [4][5] Advances have been conducted in terms of diverse nuclearities, sizes, and shapes, for instance, the general building block strategy with 'bottom-up' molecule design [6] has enabled the assemblies of POM architectures, especially giant POM entities that bridge the gaps between molecular oxo anions and in nite oxides. [7] However, the controllable preparation of giant POM clusters including precise atomic-level tailoring and structural functionality still remains a great challenge, which is highly desirable for engineering functional molecular metal oxides and fundamental understanding of how different motifs contribute to its overall properties.…”