A facile approach of layer-by-layer depositing and hydrolysis of FeCl3 is developed to fabricate 3D-ordered Fe2O3 film. The 3D-ordered Fe2O3 film was characterized by SEM, XRD, and DRUV−vis. It has 3D-ordered interconnecting macropores (340 nm) with nanocrystalline hematite Fe2O3 walls (27.2 nm). The 3D-ordered macroporous nanocrystalline Fe2O3 film exhibits 2.4 times larger photocatalytic activity for the photodegradation of dye in the presence of H2O2 under visible irradiation than the nanocrystalline α-Fe2O3 film without macropores and very good photostability. The much higher photocatalytic activity of the 3D-ordered macroporous nanocrystalline Fe2O3 film than that of the reference Fe2O3 film is attributed to the unique nanostructure and architecture of the 3D-ordered Fe2O3 film, which result in the much greater light harvesting efficiency and efficient mass transport in the former than in the latter due to the existence of 3D-ordered interconnecting macropores. The effect of photonic stop band on the photocatalytic activity of the 3D-ordered Fe2O3 film was studied by angle-dependent solid-state photodegradation experiments with monochromatic irradiation. A slow photon enhancement of photocatalytic activity was achieved by adjusting the red edge of the photonic stop band of the 3D-ordered Fe2O3 film close to the electronic bandgap of Fe2O3. The photodegradation mechanism of crystal violet on the 3D-ordered Fe2O3 photocatalyst in the presence or absence of H2O2 was discussed.

Novel 2D-ordered dome films of nano titania (2D-TiO 2 ) and nano Ag 2+ doped titania (2D-Ag-TiO 2 ) were prepared by RF magnetron sputtering method. The existence of oxygen vacancies or Ti 3+ ions in the 2D-ordered dome films extends the absorption of TiO 2 from UV region to visible region up to 530 nm. Doping of Ag 2+ in the 2D-TiO 2 film considerably enhance the visible light absorption of the 2D-Ag-TiO 2 film. Remarkably, for the photodegradation of cationic crystal violet (CV) and anionic methyl orange (MO), the 2D-ordered dome films exhibit 100% photodegradation selectivity to cationic CV. The 2D-Ag-TiO 2 film shows excellent selective photocatalytic durability and photostability without detectable photoreduction of Ag 2+ ions after long time illumination. Furthermore, the 2D-ordered dome films exhibit unique ratiometric photoelectrochemical sensing property with 100% selectivity to the cationic CV. Ag 2+ doping in the 2D-TiO 2 film significantly improves the photocatalytic activity and photoelectrochemical sensitivity as it considerably enhances the charge transfer efficiency from excited dye to titania.

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An efficient palladium-catalyzed C–H bond functionalization/ortho-monoacylation reaction of 3-aryl-1,2,4-benzotriazines with (hetero)aryl or alkyl aldehydes has been developed, which offers a facile and alternative strategy for direct modification and further diversification of 3-aryl-1,2,4-benzotriazines. Bioactive 1,2,4-benzotriazine has been employed as a novel directing group for the palladium-catalyzed regioselective monoacylation of sp2 C–H bond protocol with broad substrate scope and good functional group tolerance.

A quad-band metamaterial absorber using a periodically arranged surface structure placed on an ultra-thin substrate is demonstrated in this paper. Its surface structure consists of a rectangular patch and four L-shaped structures distributed symmetrically. The surface structure is able to have strong electromagnetic interactions with incident microwaves, thereby generating four absorption peaks at different frequencies. With the aid of the near-field distributions and impedance matching analysis of the four absorption peaks, the physical mechanism of the quad-band absorption is revealed. The usage of graphene-assembled film (GAF) provides further optimization to increase the four absorption peaks and promotes the low-profile characteristic. In addition, the proposed design has good tolerance to the incident angle in vertical polarization. The proposed absorber in this paper has the potential for filtering, detection, imaging, and other communication applications.