Isomerism in Titanium‐Oxo Clusters: Molecular Anatase Model with Atomic Structure and Improved Photocatalytic Activity

Abstract

Phase isomerism is a common and important phenomenon in inorganic materials, but the molecular isomerism of their nanocluster models is still rare. In this work, we report the first pair of isomeric titanium‐oxo clusters. Through combining pentagonal {Ti(Ti5)} building units in corner‐sharing or edge‐sharing forms, the two obtained Ti20‐oxo clusters take vertical and horizontal core configurations, respectively, which are both functionalized by the same organic ligands. More interestingly, the vertical type Ti20‐oxo core contains an identical {Ti8O14} moiety as anatase, making it the first molecular model of anatase TiO2. As a result, the vertical type cluster exhibits better photocatalytic H2 evolution activity, higher photocurrent response and faster charge transfer to external acceptors than its horizontal isomer. Thus, this work provides a cluster isomer method to understand the structure–property relationship of import titanium oxide materials.

Recent Advances in First‐Row Transition Metal Clusters for Photocatalytic Water Splitting

“…Ti 14 was the first case of TOCs comprised by the rutile‐like hexagonal {Ti 7 } unit in the structure. In the same year, Zhang's group reported the first couple of isomeric TOCs, [Ti 20 (μ 2 ‐O) 8 (μ 3 ‐O) 20 (PA) 14 (8‐OQ) 10 ] (PTC‐49 V ; PA=propionic acid, 8‐OQ=8‐hydroxyquinoline) and horizontal forms of [Ti 20 (μ 2 ‐O) 10 (μ 3 ‐O) 16 (μ 4 ‐O) 2 (PA) 14 (8‐OQ) 10 ] (PTC‐49 H ) . Although, both isomeric clusters were functionalized by the same organic ligands but with different arrangements of pentagonal {Ti(Ti 5 )} building units.…”

“…In the same year, Zhang's group reported the first couple of isomeric TOCs, [Ti 20 (μ 2 -O) 8 20 (PA) 14 16 (μ 4 -O) 2 (PA) 14 (8-OQ) 10 ] (PTC-49 H ). [72] Although, both isomeric clusters were functionalized by the same organic ligands but with different arrangements of pentagonal {Ti(Ti 5 )} building units. More interestingly, the identical {Ti 8 O 14 } moiety in the vertical type Ti 20 -oxo core existed as the anatase form, making PTC-49 V the first molecular anatase shaped TiO 2 (Figure 4).…”

A Series of Ti6 Oxo Clusters Anchored with Arylamine Dyes: Effect of Dye Structures on Photocurrent Responses

“…Therefore, the lower photocurrents of 5 and 6 in comparison with those of mono-para-substitutedd ye-TOCs should be attributed to both the reasons of weaker LMCT and higher steric hindrance. These reasonsc an also explain result (3). The poorest behavior of cluster 2 in terms of photocurrent is attributed to the fact that the donor is as imple amino group and they are meta-substituted on the benzoicacid (result 4).…”

“…Titanium oxo clusters (TOCs), being analogs of titaniumo xide but with uniform scale andp recise structures, are attractivea s ac lass of molecular models and molecular materials. [1] Aiming at exploring the potential applications of the crystalline TOCs, scientists have been making great efforts to study their properties as precursors of nanomaterials, [2] as wellasphotocatalytic [3] and photoelectric materials. [4,5] Organic ligand modified TOCs have received growinga ttentionw ith respect to the molecular level studies of dye-sensitized solar cells (DSSCs).…”

An Ultrastable Matryoshka [Hf13] Nanocluster as a Luminescent Sensor for Concentrated Alkali and Acid

“…The synthesis of highly stable polynuclear metal clusters is an important goal owing to their unique structures and versatile applications in optoelectronics, luminescence sensing, solar‐energy harvesting, and other areas . Many impressive metal clusters have been reported, with cores such as [Ti 20 ], [Au 32 ] 8+ , [Fe 42 ], [Cu 53 ], [Ag 374 ], [Gd 140 ], and [Ni 21 Gd 20 ], as well as [As@Ni 12 @As 20 ] 3− and inorganic fullerene‐like molecules . These clusters are generally sensitive toward strong acid/alkali or certain solvents, owing to attack by H + , OH − , and/or small molecules, thus tending to decompose or dissolve in water and organic solvents .…”