Three-Dimensional Hierarchical Porous TiO2 for Enhanced Adsorption and Photocatalytic Degradation of Remazol Dye.

Three-dimensional hierarchical mesoporous structures of titanium dioxide (3D-HPT) were synthesized by self-assembly emulsion polymerization. Polymethyl methacrylate (PMMA) and pluronic 123 (P123) were used as the soft templates and co-templates for assisting the formation of hierarchical 3D porous structures. The TiO2 crystal structure, morphology, and Remazol red dye degradation were investigated. The 3D-HPT and normal three-dimensional titanium dioxide (3D-T) presented the good connection of the nanoparticle-linked honeycomb within the form of anatase. The 3D-HPT structure showed greatly enhanced adsorption of Remazol dye, and facilitated the efficient photocatalytic breakdown of the dye. Surprisingly, 3D-HPT can adsorb approximately 40% of 24 ppm Remazol dye in the dark, which is superior to 3D-T and the commercial anatase at the same condition (approx. 5%). Moreover, 3D-HPT can completely decolorize Remazol dye within just 20 min, which is more than three folds faster than the commercial anatase, making it one of the most active photocatalysts that have been reported for degradation of Remazol dye. The superior photocatalytic performance is attributed to the higher specific surface area, amplified light-harvesting efficiency, and enhanced adsorption capacity into the hierarchical 3D inverse opal structure compared to the commercial anatase TiO2.

2,2'-({4-[(4-Nitro-phen-yl)diazen-yl]phen-yl}imino)-diethanol.

In the title compound, C16H18N4O4, the mol-ecule assumes an E conformation with respect to the N=N double bond. The aromatic rings are not coplanar, with a dihedral angle of 7.51 (8)°. The nitro group is tilted by 4.71 (11)° relative to the attached benzene ring. In the crystal, mol-ecules are connected through O-H⋯O hydrogen bonds forming a double-stranded chain parallel to the b axis.

3-Amino-benzoic acid-4,4'-bipyridine (2/3).

The asymmetric unit of the title compound, 3C(10)H(8)N(2)·2C(7)H(7)NO(2), consists of three mol-ecules of 4,4'-bipyridine (bpy) and two mol-ecules of 3-amino-benzoic acid (bza). Two mol-ecules of bza and two mol-ecules of bpy are connected via O-H⋯N, N-H⋯N and N-H⋯O hydrogen bonds, forming forming infinite double-stranded zigzag chains along the c axis. The third mol-ecule of bpy is linked to the chain by weak C-H⋯O inter-actions. Adjacent chains are linked via π-π inter-actions [centroid-centroid distances = 3.759 (3)-3.928 (3) Å] involving the pyridine rings of bpy mol-ecules, resulting in a sheet-like structure parallel to (100). These sheets are stacked via C-H⋯π inter-actions, resulting finally in the formation of a three-dimensional supra-molecular structure.

1-(2-Bromobenzoyl)-6,7-(methylene-dioxy)isoquinoline.

In the title mol-ecule, C(17)H(10)BrNO(3), the mean planes of tricycle and bromo-phenyl fragments form a dihedral angle of 75.5 (1)°. In the crystal, π-π inter-actions [centroid-centroid distances = 3.556 (2) and 3.898 (8) Å] between the isoquinoline systems link mol-ecules into stacks parallel to the a axis. The crystal packing also exibits weak inter-molecular C-H⋯O hydrogen bonds.

3,8-Dimethyl-4,7-diaza-deca-3,7-diene-2,9-dione dioxime.

The complete mol-ecule of the title compound, C(10)H(18)N(4)O(2), is generated by a crystallographic inversion centre at the mid-point of the central C-C bond. The two oxime groups have an E configuration. In the crystal, mol-ecules are linked through inter-molecular O-H⋯N hydrogen bonds.