•The replica of TiO2 with hierarchically porous photonic crystal structure is fabricated.•The DSSCs was fabricated by using the TiO2 replica as the light-scattering layer.•The power conversion efficiencies of DSSCs up to 8.7%.Creating new functional materials derived from the structures seen on butterfly wings has achieved interest in a variety of research topics. However, there need a concision approach could result in a high-quality, precise, and convenient process for the fabrication of complex nanostructures replication with unique functionalities based on the butterfly wings. Here we developed a pithy approach based on a magnetron sputtering metal Ti process for biotemplating used to refine hierarchically porous titanium dioxide photonic crystal nanostructures (TiO2PCN), themselves derived from nanostructures present on the wings of Sasakia Charonda Formosana (S. Charonda) butterflies. For the first time, the TiO2PCN were deposited on the top of the P25 active layer and were used to fabricate DSSCs as the light-scattering layers of photoanodes with power conversion efficiencies of up to 8.7%. Remarkably, a much enhanced photocurrent density and a prominent photoelectrochemical conversion capability have been achieved, which are exceeding most of the previously reported photoanodes as well as a similar butterflies replication-based device structure. Our study suggests many exciting opportunities of developing artificially engineered butterfly wing-based solar-to-fuel conversion.The table of contents entry: A refinement hierarchically porous TiO2 photonic crystal nanostructures derived from Sasakia Charonda Formosana butterfly wings as the biotemplating through a magnetron sputtering mental Ti process. The An inverted polycrystalline hierarchically porous TiO2 photonic crystal structure was achieved by controlling oxidation of metal Ti nanoparticles on the surface of biological structures as well as was removed the butterfly wing template at high temperature.

•The Fe3O4@MnO2 hollow spheres were synthesized.•The sorption of U(VI) on Fe3O4@MnO2 hollow spheres is spontaneous and endothermic.•The sorption of U(VI) on Fe3O4@MnO2 hollow spheres is dependent on ionic strength.•Fe3O4@MnO2 hollow spheres can be used as cost-effective material for U(VI) removal.Herein, the hydrothermal method was adopted to synthesize Fe3O4@MnO2 hollow spheres for the removal of U(VI) from aqueous solution. The effects of contact time, pH, ionic strength, solid content and temperature were investigated by using a batch technique. The sorption of U(VI) was dependent on ionic strength at pH < 7, suggesting that electrostatic interaction and/or outer-sphere surface complexation was the predominant sequestration mechanism within this pH range. In contrast, the ignorable effect of ionic strength on the sorption behaviors at pH > 7 pointed to the occurrence of inner-sphere surface complexation. Typical sorption isotherms (Langmuir, Freundlich, Dubinin-Raduskevich) were determined for the mechanism of sorption process. The maximum sorption amount of U(VI) on Fe3O4@MnO2 hollow spheres reached to 13.95 mg/g at 293 K. The thermo-dynamic parameters were calculated from the temperature isotherms, and the results suggested that U(VI) sorption on Fe3O4@MnO2 hollow spheres was a spontaneous and endothermic process. The results might be important for the application for U(VI) pollution management.

For the first time, we report a one-step fabrication of an environment-friendly approach to synthesize flower-like α-Fe2O3 hierarchical nanoparticles (NPs)/reduced graphene oxide (RGO) hybrids by combining the graphene oxide (GO) with the growth of α-Fe2O3 NPs. The GO sheet which possesses the functional group, such as hydroxyl (–OH) and carbonyl groups (–OOH), can be easily incorporated with the petal of the flower-like α-Fe2O3 in ethanol and water solution through a solvothermal process, during which GO is reduced to RGO without the addition of any strong reducing agent or requiring any post-high-temperature annealing process. The as-prepared samples are loose and porous with flower-like structure, and the RGO hybrids were wrapped up uniformly on the sheet of α-Fe2O3 NPs. To demonstrate the potential applications, we have fabricated dye-sensitized solar cells (DSSCs) from the as-synthesized hierarchical flower-like α-Fe2O3/RGO and investigated it for the photoanode of DSSCs. Results show that the hierarchical α-Fe2O3/RGO solar cell exhibits improved performances in comparison with the free α-Fe2O3 NPs. The enhancement of photovoltaic properties is attributed to the unique porous nature and good conductivity which allow more efficient diffusion of I− ions and facilitate the transfer of electron in the network.

•The Fe3O4@cyclodextrin magnetic composite was synthesized.•Fe3O4@CD MCs could be easily separated with an external magnetic field.•The sorption of Eu(III) on Fe3O4@CD MCs is dependent on foreign anions.•Fe3O4@CD MCs can be used as cost-effective material for Eu(III) removal.In this study, the Fe3O4@CD MCs were synthesized by using a simple chemical co-precipitation method for the removal of Eu(III) from aqueous solutions. Compared with Fe3O4, the prepared Fe3O4@CD MCs exhibited higher sorption amount toward Eu(III). In addition, Fe3O4@CD MCs could be easily separated from aqueous solutions by using magnetic separation technique at low magnetic field gradients. The sorption properties of Fe3O4@CD MCs toward Eu(III) were investigated by using a batch technique under environmental conditions. The sorption kinetics of Eu(III) on Fe3O4@CD MCs could achieve equilibrium in a time period of 3 h. The pH-dependent and ionic strength-independent Eu(III) sorption on the surface of Fe3O4@CD MCs demonstrated that the sorption mechanism of Eu(III) was inner-sphere surface complexation at low pH, whereas the removal of Eu(III) was achieved by simultaneous precipitation and inner-sphere surface complexation at high pH values. The Langmuir and Freundlich patterns were employed to simulate sorption isotherms of Eu(III) on Fe3O4@CD MCs. Considering the low cost, simple synthesis procedure, high removal efficiency, easy separation and environmental friendliness, it is expected that Fe3O4@CD MCs can be used as a cost-effective material for the purification of Eu(III)-bearing effluents.

•Axle-sleeve structured MWCNT/PANI composite was prepared.•The optimum mass ratio of MWCNT/ANIranges between 1:3 and 1:1.•The π-π drive force was confirmed by spectroscopicmeans.•The polymerization time of 12∼24 hrs affords the highest conversion efficiency.•The DSSCs assembled with the MWCNTs/PANI CEs exhibit a comparable η(7.21%) as that with Pt CE (7.59%).Axle-sleeve structured composite materials made with multi-walled carbon nanotubes (MWCNTs) and polyaniline (PANI) were prepared, characterized, and employed as cost-effective counter electrodes (CEs) in dye-sensitized solar cells (DSSCs). The composite was synthesized by co-polymerization of aniline with carboxylated MWCNTs by using ammonium persulfate in the acidic medium. Thin films of MWCNTs/PANI were prepared via a spin coating technique followed by thermal treatment in N2 atmosphere. The micro-structure of the composite was studied by scanning electron microscopy (SEM) and transmission electron microscopy (TEM) linked with energy dispersive spectroscopy (EDS). The coating layer of PANI on the MWCNTs and new-formed chemical bonds between MWCNTs and PANI was studied by UV-Vis absorption, X-ray photoelectron spectroscopy (XPS), Raman and FT-IR spectroscopic means. The effect of the multiple-level porosity or the axle-sleeve structures in the composite of MWCNTs/PANI on the electro-catalytic activity was investigated by cyclic voltammetry (CV) and electrochemical impedance spectroscopic (EIS) analysis. The DSSCs assembled with MWCNTs/PANI as CEs exhibit a comparable energy conversion efficiency (η) of 7.21% as compared to that of a DSSC consisting of a screen-printed Pt CE (η = 7.59%). These promising results propose a potential application of MWCNTs/PANI in cost-effective DSSCs.Axle-sleeve structured composite materials made with carbon nanotubes and polyaniline were prepared via a co-polymerization strategy. The composite materials were employed as cost-effective counter electrode modifier in dye-sensitized solar cells which demonstrate a comparable photo-to-electron conversion efficiency as the Pt catalyst.

Yolk–shell microspheres with magnetic Fe3O4 cores and hierarchical magnesium silicate shells (Fe3O4@MS) have been successfully synthesized by combining the versatile sol–gel process and hydrothermal reaction. The as-prepared Fe3O4@MS microspheres were then assessed as the adsorbent for uranium(VI) removal from water, and could be easily separated by an external magnetic field. Influencing factors to adsorb uranium(VI) were investigated, including pH, ionic strength and coexisted ions, amount of adsorbent and equilibrium time. The results indicated that uranium(VI) adsorption on Fe3O4@MS microspheres was strongly dependent on pH and the ionic strength. The maximum adsorption capacity for uranium(VI) was calculated to be 1.51 × 10−5 mol g−1 based on the Langmuir model and the experimental data fitted the Langmuir model (R2 = 0.999) better than the Freundlich model (R2 = 0.954). The as-prepared sub-microspheres showed their potential applications as adsorbent for highly efficient removal of heavy metal ions from wastewater.

We investigated a facile multifunctionalized hierarchical SnO2 nanoflower photoelectrode passivated by a layer of TiO2 nanogranulum. The hierarchical SnO2 nanoflower with thin nanorod and nanosheet has a unique morphology that can afford excellent electron transport properties—orientation overall, which results in a significant diminution in the charge diffusion route and a rapid collection in FTO substrate. The passivated photoanode not only improved the distribution of dyes in the photoelectrode and reduced the surface defects of SnO2 photoelectrode to accommodate more dyes, but also suppressed the charge recombination and prolonged electron lifetime by introducing a barrier layer. The microstructure of the sample was investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The surface areas (SBET) and pore size distribution were detected on BET measurement. The amounts of dye were calculated from UV–vis. The interfacial charge transfer process and the charge recombination were characterized by EIS and IMPS/IMVS measurements. The DSSCs assembled with multifunctionalized photoanode exhibits favorable energy conversion efficiency. The photocurrent increased from 5.44 to 12.74 mA cm2, the photovoltage from 440 to 760 mV, and the fill factor from 43.58% to 57.58%. As a result, the cell’s conversion efficiency increased by a factor of 5.3 from 1.05% to 5.60%. The increase in efficiency originates from higher open-circuit potential and higher short-circuit current as well as from superior light scattering effect, long electron lifetime, and slower electron recombination.

A green and simple method was found to prepare CdS/CdSe co-sensitized photoelectrodes for the quantum dots sensitized solar cells application. All the assembly processes of CdS and CdSe quantum dots (QDs) were carried out in aqueous solution. CdS and CdSe QDs were sequentially assembled onto TiO2-nano-SiO2 hybrid film by two steps. Firstly, CdS QDs were deposited in situ over TiO2-nano-SiO2 hybrid film by the successive ionic layer adsorption and reaction (SILAR) process in water. Secondly, using 3-mercaptopropionic acid (3-MPA) as a linker molecule, the pre-prepared colloidal CdSe QDs (~3.0 nm) dissolved in water was linked onto the TiO2-nano-SiO2 hybrid film by the self-assembled monolayer technique with the mode of dropwise. The mode is simple and advantageous to saving materials and time. The results show that the photovoltaic performance of the cells is enhanced with the increase of SILAR cycles for TiO2-nano-SiO2/CdS photoelectrode. The power conversion efficiency of 2.15 % was achieved using the co-sensitization photoelectrode prepared by using 6 SILAR cycles of CdS plus CdSe (TiO2-nano-SiO2/CdS(6)/CdSe) under the illumination of one sun (AM1.5, 100 mW/cm2).

The Langmuir–Blodgett (LB) technique has been employed for the construction of a model of interfacial supported ionic liquids (ILs) catalyst. In this model a hybrid LB film consists of three components: ionic liquids (imidazolium chloride with different length of substituent alkyl chain), catalyst carrier (saponite and laponite), and catalyst species (platinum nanocrystals). It was found imidazolium ILs with carbon number more than six in the alkyl substituents can form stable Langmuir monolayer over diluted clay dispersions. By recording surface pressure versus time (π–t) kinetic curves, we found that the adsorption of imidazolium ILs or platinum nanocrystals by clay elementary layers reaches equilibrium within 200 s, and the molar Gibbs free energy change −dG (kJ mol–1) for the adsorption lies in the range 0.34–5.6 kJ mol–1. Surface pressure versus area (π–A) isotherms revealed that platinum nanocrystals are adsorbed by the IL–clay Langmuir films at the air–water interface, and there are two phase transition points in the π–A isotherms during the compression of IL–clay–Pt. We utilized two methods, i.e., interfacial chemical methods (π–t, π–A) and spectroscopic measurements (UV–vis absorption, atomic absorption spectroscopy (AAS)) to quantify the amount of imidazolium IL and Pt that are presented in the LB films. Results showed that the amount of adsorbed 1-hexadecyl-3-methylimidazolium chloride (C16MIM) in the hybrid film C16MIM–saponite–Pt at the first deposition layer is around 0.65 ng mm–2. Laponite gives a higher adsorption capacity for loading IL and Pt nanocrystals. Attenuated total reflectance (ATR)–Fourier transform infrared spectra (FTIR) confirmed the presence of IL in the LB film which shares ordered vibrational conformation, and the degree order of C16MIM molecules becomes worse after incorporation of Pt nanocrystals. Transmission electron microscopy (TEM) verified that Pt nanoparticles with size of ∼5.0 nm tend to be adsorbed on the edges of clay layers, and the surface coverage of Pt particles can be tuned by the compression pressure. The Pt-containing LB films were deposited on a glass carbon electrode (GCE), and the electrocatalytic performance toward methanol electro-oxidation and synergistic effects between the three components have been studied by means of cyclic voltammetry (CV) and chronoamperometry (CA). The results indicated that the film IL–clay–Pt exhibits a remarkable enhancement in catalytic activity and stability compared to clay–Pt in terms of the onset potential for methanol oxidation, the specific mass current density based on the amount of Pt catalyst, and the slower decay of steady-state current in the CA profile.