Synthesis and Photocatalytic Properties of a New Heteropolyoxoniobate Compound: K₁₀[Nb₂O₂(H₂O)₂][SiNb₁₂O₄₀]·12H₂O

Abstract

The synthesis and photocatalytic properties of a heteropolyoxoniobate, K(10)[Nb(2)O(2)(H(2)O)(2)][SiNb(12)O(40)]·12H(2)O (1), are reported, revealing an important role of Zr(4+) additives in the crystallization. Compound 1 exhibits overall photocatalytic water splitting activity, and its photocatalytic activity is significantly higher than that of Na(10)[Nb(2)O(2)][SiNb(12)O(40)]·xH(2)O (2). Fluorescence lifetime measurements suggest that the enhanced photocatalytic activity of 1 likely results from a larger yield of longer-lived charge trapping states in 1 due to the coordination of one water molecule to the bridging Nb(5+), leading to highly unsymmetrical seven-coordinated Nb(5+) sites.

Soluble Heteropolyniobates from the Bottom of Group IA

“…x H 2 O and Na 10 [Nb 2 O 2 ][TNb 12 O 40 ]·x H 2 O (T= Si or Ge) (D), [13] Na 15 [(PO 2 ) 3 PNb 9 O 34 ]·22 H 2 O (E), [14] K 10 [Nb 2 O 2 ]-[GeNb 12 O 40 ]·11 H 2 O (F), [15] Li 13 12 O 40 ]· 12 H 2 O (H). [16] Many of these are composed of polyanions linked into framework-like layers or chains through corner-(H) or edge-sharing of Ti=O and Nb=O caps (A, D, and F). Even those clusters that are considered to be isolated in the crystalline lattice, separated only by water molecules and alkali-metal counterions (C, E, and G), are insoluble, and thus neither solution characterizations nor solution stabilities were documented.…”

A molecular crown analogue templated by Keggin polyanions: synthesis, structure, and electrochemical and luminescent properties

“…Generally, the metalorganic macrocycle possesses positive charge, and thus it needs a counteranion to keep charge balance. Polyoxometalates (POMs), a unique class of anionic clusters, can be used not only as counteranions but also as templates that are conducive to the formation of macrocyclic compounds [9][10][11][12][13][14][15][16][17][18][19]. Furthermore, such POM-based macrocyclic compounds could combine the advantages of both the POMs and the macrocycles and open up new possibilities in the pursuit of multifunctional materials with designed functional properties and aesthetic topological structures [6,8,19].…”

Visible‐Light‐Responsive β‐Rhombohedral Boron Photocatalysts

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Photocatalytic solar-energy conversion has been attracting worldwide attention owing to its great significance in the provision of renewable energy and protection of the environment. [8][9][10][11][12][13][14][15][16] So far, hundreds of photocatalysts have been examined, most of which have been compounds. [8][9][10][11][12][13][14][15][16] So far, hundreds of photocatalysts have been examined, most of which have been compounds.

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“…[1][2][3] As important as the tailoring of well-known photocatalysts, such as TiO 2 , for high photocatalytic efficiency [4][5][6][7] is the investigation of unknown semiconductor photocatalysts. [8][9][10][11][12][13][14][15][16] So far, hundreds of photocatalysts have been examined, most of which have been compounds. [3,17,18] Recently, elemental semiconductors (Si, Se, P, S) have emerged as an attractive class of photocatalysts owing to their visible-light response and suitable band edges for targeted photocatalysis reactions.…”