Soft-template-assisted synthesis: a promising approach for the fabrication of transition metal oxides

The past few decades have witnessed transition metal oxides (TMOs) as promising candidates for a plethora of applications in numerous fields. The exceptional properties retained by these materials have rendered them of paramount emphasis as functional materials. Thus, the controlled and scalable synthesis of transition metal oxides with desired properties has received enormous attention. Out of different top-down and bottom-up approaches, template-assisted synthesis predominates as an adept approach for the facile synthesis of transition metal oxides, owing to its phenomenal ability for morphological and physicochemical tuning. This review presents a comprehensive examination of the recent advances in the soft-template-assisted synthesis of TMOs, focusing on the morphological and physicochemical tuning aided by different soft-templates. The promising applications of TMOs are explained in detail, emphasizing those with excellent performances.

Oxygen-defect-dependent ferromagnetism and strain modulation in free-standing two-dimensional TiO2 monolayers

Recently, layered two-dimensional titania (2D-TiO2) with a reduced band gap has been successfully synthesized. However, as an important application in spintronics, ferromagnetism in this material has not been investigated so far. To obtain the expected ferromagnetism, the formation and stability of the most prominent oxygen defects in a TiO2 monolayer under different external strains were explored systematically. The calculated results disclosed that structural deformation induced by tensile strain not only led to changes in the oxygen defect formation energy but also modified its magnetic features. With an increase in compressed strain, the Curie temperature in this system decreased due to insufficient spin polarization. Our calculations provide a strategy to utilize oxygen defect and strain engineering to realize applications of 2D TiO2 monolayers in spintronics.

Fabrication and Properties of a Free-Standing Two-Dimensional Titania

The synthesis of free-standing two-dimensional titania (2-D TiO₂) with a reduced band gap presents complex challenges to synthetic chemists. Here, we report a free-standing 2-D TiO₂ sheet synthesized via a one-step solvothermal methodology, with a measured optical onset at ∼1.84 eV. Using first-principles calculations in combination with experiment, we propose that the as-formed 2-D TiO₂ sheets are layers of the lepidocrocite TiO₂ structure, but with large nonuniform strains consistent with its crumpled morphology. These strains cause a significant change in the quasiparticle band structure and optical absorption spectra, resulting in large absorption in the visible-light region. This narrow band gap 2-D TiO₂ can catalyze the formation of singlet oxygen and the degradation of dye pollutants with low-energy photons of solar light. Our work demonstrates that lattice strains intrinsic to 2-D materials, especially its crumpled, free-standing forms, can result in new and useful properties.

Applications of inorganic nanoparticles as therapeutic agents

During the last decade, various functional nanostructured materials with interesting optical, magnetic, mechanical and chemical properties have been extensively applied to biomedical areas including imaging, diagnosis and therapy. In therapeutics, most research has focused on the application of nanoparticles as potential delivery vehicles for drugs and genes, because nanoparticles in the size range of 2-100 nm can interact with biological systems at the molecular level, and allow targeted delivery and passage through biological barriers. Recent investigations have even revealed that several kinds of nanomaterials are intrinsically therapeutic. Not only can they passively interact with cells, but they can also actively mediate molecular processes to regulate cell functions. This can be seen in the treatment of cancer via anti-angiogenic mechanisms as well as the treatment of neurodegenerative diseases by effectively controlling oxidative stress. This review will present recent applications of inorganic nanoparticles as therapeutic agents in the treatment of disease.