Bioprocess-inspired Actin Biomineralized Hematite Mesocrystals for Energy Storage

Biomineralization is a biological process of synthesizing inorganic minerals within organisms.It has been found that intracellular proteins are involved in the room temperature synthesis process of anatase Ti O2in living mussels.Here,we used intracellular actin to synthesize hematite by biomineralization.Biomineralized hematite has a nano spindle structure with a particle size of approximately 150 nm.The microstructure indicates that the prepared hematite is a mesocrystals composed of ordered arrangement and assembly of primary nanoparticles.In addition,hematite mesocrystals exhibit good lithium storage performance as electrode materials for lithium batteries.The discharge specific capacity of the battery remained at 560.7 m Ah·g^(-1)after 130 cycles at a current density of 200 m A·g^(-1).This work expands the synthesis methods of hematite by biomineralization,and provides a new strategy for preparing inorganic materials by intracellular proteins.

Development of tailored TiO_2 mesocrystals for solar driven photocatalysis

Ordered metal oxides superstructures have attracted much more attention in the fields of fuel generation and environmental purification owing to their unique physiochemical characteristics such as large surface area, fine pore structure, efficient electronic mobility, and good stability. Very recently, TiOmesocrystals（TMCs） having superstructures self-assembled by TiOnanoparticle building blocks, are of considerable interest in current research and application ranging from UV to visible light attributed to their efficient charge separation and superior photocatalytic activity. In this review, we describe the common procedures to prepare unique TMCs and overview of recent developments of TMCs during last 3 years, especially the structure-related or electronic-effected mechanism in photocatalytic reaction. Further, we introduce the characterization and fundamental properties of modified TMCs by the means of single-particle fluorescence microscopy for unraveling the charge transport and photocatalytic properties of individual TMCs and time-resolved diffuse reflectance spectroscopy（TDR） for monitoring the charge transfer dynamics. Finally, various aspects on TMCs are discussed for the future developments of energy and environmental fields.

Mesocrystalline TiO2/sepiolite composites for the effective degradation of methyl orange and methylene blue

Mesocrystalline TiO2/sepiolite （TiS） composites with the function of adsorption and degradation of liquid organic pollutants were successfully fabricated via a facile and low-cost solvothermal reaction. The prepared TiS composites were characterized by FESEM, HRTEM, XRD, XPS, N2 adsorption-desorption, UV-vis DRS, and EPR. Results revealed the homogeneous dispersion of highly reactive TiO2 mesocrystals on the sepiolite nanofibers. Thereinto each single-crystal-like TiO2 mesocrystal comprised many [001]-oriented anatase nanoparticles about 10-20 nm in diameter. The photocatalytic activity was further evaluated by the degradation of anionic dye （methyl orange） and cationic dye （methylene blue） under the UV-vis light （350≤λ≤780 nm） irradiation. By selecting appropriate experimental conditions, we can easily manipulate the photocatalytic performance of TiS composites. The optimal TiS catalyst （the sepiolite content of 28.5 wt.%, and the reaction time of 24 h） could efficiently degrade methyl orange to 90.7% after 70 min, or methylene blue to 97.8% after 50 min, under UV-vis light irradiation. These results can be attributed to their synergistic effect of high crystallinity, large specific surface area, abundant hydroxyl radicals, and effective photogenerated charge separation.

A general bottom-up synthesis of CuO-based trimetallic oxide mesocrystal superstructures for efficient catalytic production of trichlorosilane

Mesocrystals, the non-classical crystals with highly ordered nanoparticle superstructures, have shown great potential in many applications because of their newly collective properties. However, there is still a lack of a facile and general synthesis strategy to organize and integrate distinct components into complex mesocrystals, and of reported application for them in industrial catalytic reactions. Herein we report a general bottom-up synthesis of CuO-based trimetallic oxide mesocrystals (denoted as CuO-M1Ox-M2Oy, where M1 and M2 = Zn, In, Fe, Ni, Mn, and Co) using a simple precipitation method followed by a hydrothermal treatment and a topotactic transformation via calcination. When these mesocrystals were used as the catalyst to produce trichlorosilane (TCS) via Si hydrochlorination reaction, they exhibited excellent catalytic performance with much increased Si conversion and TCS selectivity. In particular, the TCS yield was increased 19-fold than that of the catalyst-free process. The latter is the current industrial process. The efficiently catalytic property of these mesocrystals is attributed to the formation of well-defined nanoscale heterointerfaces that can effectively facilitate the charge transfer, and the generation of the compressive and tensile strain on CuO near the interfaces among different metal oxides. The synthetic approach developed here could be applicable to fabricate versatile complicated metal oxide mesocrystals as novel catalysts for various industrial chemical reactions.

Mesocrystalline TiO2 nanosheet arrays with exposed {001} facets： Synthesis via topotactic transformation and applications in dye-sensitized solar cells

A facile, fluorine-free approach for synthesizing vertically aligned arrays of mesocrystaUine anatase TiO2 nanosheets with highly exposed {001} facets was developed through topotactic transformation. Unique mesocrystalline {001}-faceted TiO2 nanosheet arrays vertically aligned on conductive fluorine-doped tin oxide glass were realized through topotactic conversion from single-crystalline precursor nanosheet arrays based on lattice matching between the precursor and the anatase crystals. The morphology and microstructure of the {001}-faceted TiO2 nanosheets could be readily modulated by changing the reactant concentration and annealing temperature. Owing to enhanced dye adsorption, reduced charge recombination, and enhanced light scattering arising from the exposed {001} facets, in addition to the advantageous features of low-dimensional structure arrays （e.g., fast electron transport and efficient charge collection）, the obtained TiO2 nanosheet arrays exhibited superior performance when they were used as anodes for dye-sensitized solar cells （DSSCs）. Particularly, {001}-faceted TiO2 nanosheet arrays -15 μm long annealed at 500 ℃ showed a power conversion efficiency of 7.51%. Furthermore, a remarkable efficiency of 8.85% was achieved for a DSSC based on doubleqayered TiO2 nanosheet arrays -35 μm long, which were prepared by conversion from the precursor nanoarrays produced via secondary hydrothermal growth.

Self-supported yttria-stabilized zirconia mesocrystals with tunable mesopores prepared by a chemi-thermal process

Mesoporous mesocrystals are highly desired in catalysis,energy storage,medical and many other applications,but most of synthesis strategies involve the usage of costly chemicals and complicated synthesis routes,which impede the commercialization of such materials.During the sintering of dense ceramics,coarsening is an undesirable phenomenon which causes the growth of the grains as well as the pores hence hinders the densification,however,coarsening is desired in the sintering of porous ceramics to expand the pore sizes while retaining the total pore volume.Here we report a chemi-thermal process,during which nanocrystallite aggregates were synthesized by hydrothermal process and then converted to the product by sintering.Through this strategy,we synthesized mesoporous self-supported mesocrystals of yttria-stabilized zirconia with tunable pore size and the process was then scaled-up to industrial production.The thermal conductivity measurement shows that the mesoporous powder is a good thermal isolator.The monolith pellets can be obtained by SPS sintering under high pressure and the mesoporosity is retained in the monolith pellets.This work features facile and scalable process as well as low cost raw chemicals making it highly desirable in industrial applications.

Hierarchical Silver Indium Tungsten Oxide Mesocrystals with Morphology-, Pressure-, and Temperature-Dependent Luminescence Properties

Highly hierarchical structures of silver indium tungsten oxide(AgIn(WO_(4))_(2))mesocrystals can be rationally fabricated via the microwave-assisted synthesis method by tuning the initial concentrations of the precursors.Photoluminescence spectra of hierarchical AgIn(WO_(4))_(2) mesocrystals were measured to investigate the correlation between the morphology,pressure,and temperature and their luminescence properties.The materials showed interesting white emission when excited by visible light of wavelength 460 nm.AgIn(WO_(4))_(2) materials having different morphologies displayed notable differences in photogenerated emission performance.The emission was strongly correlated with the surface nanostructures of outgrowths,with larger amounts of outgrowths leading to stronger emission intensities.The pressure-and temperature-dependent photoluminescence properties of these materials have also been investigated under hydrostatic pressures up to 16 GPa at room temperature and in the temperature range from 10 to 300 K.

Metal oxide mesocrystals and mesoporous single crystals:synthesis,properties and applications in solar energy conversion

Metal oxide mesocrystals(MCs)and mesoporous single crystals(MSCs)exhibit superior carrier transport ability,high specific surface area,shortened photo-carrier diffusion lengths to interfaces and enhanced absorbance of the incident sunlight.These advanced features make metal oxide MCs and MSCs be a promising candidate material in photocatalysis,photoelectrocatalysis,dye sensitized solar cells(DSSCs)and perovskite solar cells(PSCs).Recently,remarkable advances of applying metal oxide MCs and MSCs in these areas have been achieved.Therefore,it is extremely important to deeply understand the influence of the unique properties of metal oxide MCs and MSCs on solar energy conversion systems.Herein,we presented a brief introduction on the synthesis and carrier transfer behavior of metal oxide MCs and MSCs.Then,the rational structure design and modification of metal oxide MCs and MSCs for photocatalysis,photoelectrocatalysis,DSSCs and PSCs are systematically discussed.Finally,the perspectives on extending the application of metal oxide MCs and MSCs are addressed.

Enhanced Photocatalytic Activity of Z-scheme Meso-BiVO_(4)-Au-CdS for Degradation of Rhodamine B

We synthesized BiVO_(4)mesocrystals with ordered assembly structure,and studied the structural order and the relationship between the photodegradation of Rhodamine B.Au nanoparticles(NPs)were successfully loaded onto Meso-BiVO_(4)by light-assisted induction,and Cd nanoparticles were further selected to be deposited on Au nanoparticles to form Z-scheme photocatalyst Meso-BiVO_(4)-Au-CdS heterostructures.We try and propose to analyze its ordered assembly structure by XRD for the first time.The results show that Meso-BiVO_(4)is a mesocrystal with highly exposed(001)plane and directional assembly structure.The charge separation efficiency of all samples was studied by PL spectroscopy.The results show that the Z-scheme Meso-BiVO_(4)-Au-CdS can promote the charge separation and obtain the best carrier separation efficiency.Thus,it has the best photocatalytic activity in the experiment of photocatalytic degradation of rhodamine B.The main active species in the degradation process were confirmed by free radical trapping experiment,and the degradation mechanism was put forward.