Inorganic-organic hybrid photocatalysts:Syntheses,mechanisms,and applications

Inorganic-organic hybrid materials are promising for application in the field of photocatalysis because of their excellent properties.Therefore,their syntheses,mechanisms,and applications are reviewed in this paper.First,we introduce the role of inorganic-organic photocatalysts,their advantages and disadvantages,and their design principles.Second,we present the top-down and bottom-up synthesis methods of the hybrid materials.The interaction between inorganic and organic components in hybrid materials is discussed,followed by how to improve inorganic-organic photocatalysts.Third,the applications of hybrid materials in the field of photocatalysis,such as realizing hydrogen evolution,organic pollutant degradation,heavy metals and CO_(2) reduction,sterilization,and nitrogen fixation,are examined.Finally,the application prospects and development directions of inorganic-organic hybrid materials are explored and the unsolved problems are described.

A Novel Inorganic-organic Hybrid Borate with Unique One-dimensional Infinite Aluminium-oxygen Chains

A novel inorganic-organic hybrid borate,[Al2（fum）（H3BO3）（OH） 4]n·n（H3BO3） （1,H2fum = fumaric acid） ,has been synthesized and characterized by single-crystal X-ray diffraction,FTIR and elemental analysis. Crystal data for compound 1： orthorhombic,space group Pnma,a = 14.108（3） ,b = 6.9412（14） ,c = 14.995（3）A,V = 1468.3（5）A^3,Z = 4,Mr = 359.72,Dc = 1.627 g/cm^3,μ = 0.254 mm^-1,F（000） = 736,the final R = 0.0492 and wR = 0.1650 with I 〉 2σ（I） . In compound 1,each Al^Ⅲ ion is coordinated by six oxygen atoms to adopt a distorted octahedral geometry. Both fumarate anion and the coordinated boric acid act as bidentate bridging ligands to link two neighboring Al^Ⅲ centers simultaneously. Each Al^Ⅲ ion is bridged by two μ2-hydroxyl ligands to construct an infinite wave-like [Al2（fum）（H3BO3）（OH） 4]n chain. These one-dimensional chains form hydrogen bonds with free boric acid molecules giving rise to a three-dimensional supramolecular network.

An ionic 2D inorganic-organic hybrid of tris[((1H-tetrazol-5-yl)methyl)morpholine] dodecatungstophosphate(Ⅴ) pentahydrate:Synthesis X-ray crystal structure and spectroscopic characterizations

A unique ionic hybrid material[C_6H_(12)N_5O]_3[(PO_4)W__(12)O_(36)]·5H_2O has been synthesized from the reaction of((1H-tetrazole-5- yl)methyl)morpholine andα-H_3[(PO_4)W_(12)O_(36)]·21H_2O.It has successfully been characterized by elemental analysis,IR and ~1H NMR spectroscopies,TGA and single-crystal X-ray diffraction method.The title compound is constructed from the three [C_6H_(12)N_5O]^+ cations andα-Keggin[(PO_4)W_(12)O_(36)]^(3-) polyoxoanion.The most remarkable structural feature of this hybrid can...

A New Inorganic-organic Hybrid Based on Biisoquinoline and Hexachloridostannate:Structure, Photoluminescence, Electrochemical Behavior and Theoretical Study

A new inorganic-organic hybrid constructed from biisoquinoline dication and tin halide, [（BIQBT）（Sn Cl6）]n（1, BIQBT = 1,4-bis（isoquinoline） butane）, has been synthesized and structurally determined by X-ray diffraction method. 1 crystallizes in the monoclinic system, space group Cc with Mr = 644.82, a = 16.589（3）, b = 18.388（4）, c = 8.5532（17）A, β = 108.75（3）°, V = 2470.6（9） A3, Z = 4, Dc = 1.736 g/cm^3, F（000） = 1281, μ（Mo Kα） = 1.697 mm^–1, the final R = 0.0197 and wR = 0.0493 for 4614 observed reflections with I 〉 2（I）. 1 consists of BIQBT^2＋dications and mononuclear hexachloridostannate Sn Cl62- anion, and hydrogen bonds among them contribute to the formation of a 1-D chain. Strong fluorescence can be detected in 1, which was explained by theoretical calculation. Its electrochemical behavior was investigated, and the theoretical calculations reveal that the π···π stacking interaction is dominated for their structural stabilization.

Hydrothermal Synthesis and Crystal Structure of Inorganic-organic Hybrid Compound [H_3NC_2H_4NH_2]VOPO_4

An inorganic-organic hybrid compound, [H_3NC_2H_4NH_2]VOPO_4 was synthesized by means of the hydrothermal method. It was crystallized in a monoclinic system, a space group P2_1/c, with the crystal cell parameters: a=0.92285(11) nm, b=0.72994(9) nm, c=0.98495(11) nm, β=101.280(3)°, V=0.65067(13) nm^3, M_r=223.02 g/mol, D_c=2.277 g/cm^3, Z=4, R=0.0315, ωR=0.0865, GOF=1.085. The VO_5N octahedra chains are corner-linked by PO_4 tetrahedra; the VO_5N octahedra are all trans-linked with V—O bonds being alternately short and long. The monoprotonated ethylenediamine was intercalated between the layers with one end coordinating to V and the other end as an H-bond donor interacting with a terminal O atom of PO_4 from a neighboring sheet. The elementary analysis, infrared spectrum characters and thermal stability were also given.

Supramolecular Structural Inorganic-organic Hybrid[(4-Bromoanilimiun)([18]crown-6)]3[PMo(12)O(40)]·CH3CN

A novel supramolecular structural inorganic-organic hybrid [（4-bromoanilimiun）（[18]crown-6）]3[PMo（12）O40]·CH3 CN has been synthesized through standard solvent evaporated method. The structure of the title compound was determined through single-crystal X-ray diffraction analysis. It crystallizes in monoclinic system with P21/n space group. The crystal data are a = 18.9529（4）, b = 26.4444（5）, c = 19.0985（4） A, β = 90.132（6）o, V = 9572.1（3） A^3, Z = 4, Dc= 2.203 g·cm^（–1）, μ = 14.956 mm^（–1）, F（000） = 6192, S = 1.098, the final R = 0.0859 and w R（I 〉 2σ（I）） = 0.2100. Supramolecular cations are constructed through strong N–H…O hydrogen bonding interaction between the six oxygen atoms of [18]crown-6 molecule and nitrogen atom of（4-bromoanilimiun） cation. Three kinds of different arranged supramolecular cations exist in the title compound, which are filled into the large space formed by [PMo（12）O40] polyoxoanions. Thermogravimentic differential thermal analysis revealed that hydrogen bonding interaction and intermolecular interaction play an important role in maintaining the stability of the title compound.

Synthesis, Structure, and Photoluminescence Property of a Novel One-dimensional Inorganic-organic Hybrid Gallophosphate JGP-2

A novel one-dimensional inorganic-organic hybrid gallophosphate compound, Ga（2,2＇-bipy）（HPO4）. （H2PO4）（denoted JGP-2） was synthesized hydrothermally with 2,2＇-bipyridine as a ligand and characterized by X-ray powder diffraction （XRD）, elemental analysis, inductively coupled plasma（ICP）, TGA analysis, solid-state ^31p NMR, and luminescence spectra and structurally determined by single-crystal X-ray diffraction analysis. JGP-2 crystallized in the triclinic system, space group P^-1（No.2）, with a=0.7818（1） nm, b=0.8611 （2） nm, c=1.0908（2） nm, V=0.6727（2） nm^3 and Z=2 with R1=0.0223. The structure of JGP-2 was built up by alternate arrangement of GaO4N2 octahedra, and HPO4（or H2PO4） tetrahedra to form an infinite one-dimensional corner-sharing-corner（CSC） chain. Through P sites, the CSC chains link with an unusual edge-sharing dimmer, Ga2F4（H2O）2, giving rise to a 4,10-membered ring net layered structure of JGP-7. On excitation at 254 nm, JGP-2 can emit strong blue light at ,λmax=388 rim. JGP-7 presents a strong fluorescence emission band centered at 394 nm（λex=340 nm）, the emission energy of JGP-7 is red-shifted comoared with that of JGP-2.

New Inorganic-organic Hybrid Compound Containing One Dimensional Keggin Polyoxometalate [SiW_(11)O_(39)Co]^(6-) Chains: Preparation, Characterization and Application in Chemically Bulk-modified Electrode

A new inorganic-organic hybrid compound based on polyoxometalate and organic ligand formulated as （H2bpp）3[SiWlIO39Co]-2H20（1）[bpp=l,3-bis（4-pyridyl）propane] was hydrothermally synthesized and structurally characterized by elemental analysis, single-crystal X-ray diffraction, IR, TG, and cyclic voltammetry. Single-crystal X-ray diffraction analysis reveals that compound 1 consists of interesting cobalt-monosubstituted POMs one dimensional chain together with protonated bpp ligands. Additionally, the polyoxoanions combined with the discrete organic substrates by hydrogen bond interactions to afford a supramolecular 3D network structure. The hybrid compound 1 was used as a bulk modifier to fabricate a three-dimensional chemically modified carbon paste electrode（1-CPE） by direct mixing. The electrochemical behavior and electrocatalysis of 1-CPE were studied in detail. The results indicate that 1-CPE has good electrocatalytic activities toward the reduction of nitrite or bromate in 1 mol/L 1-12SO4 aqueous solution. 1-CPE shows remarkable stability that can be ascribed to the insolubility of compound 1 and the supramolecular interactions existed between 1D POM anion chains and organic ligand bpp, which is very important for practical applications in electrode modification.

The Inorganic-organic Hybrid Junction with n-ZnO Nanorods/p-polyfluorene Structure Grown with Low-temperature Aqueous Chemical Growth Method

The inorganic-organic hybrid junction was synthesized on ITO glass substrate, which was consisted of an n-type ZnO nanorods （NRs） grown by low-temperature aqueous chemical growth method and a p-type polyfluorene （PF） organic film fabricated by spin-coating. The experimental results indicate that densely and uniformly distributed ZnO nanorods are successfully grown on the PF layer. The thickness of the PF layer plays a dominant role for the current-voltage （I-V） characteristic of the ZnO NRs/PF inorganic-organic hybrid junction device, and a p-n junction with obviously rectifying behavior is achieved with optimal PF layer thickness. The photoluminescence （PL） spectrum covering the broad visible range was obtained from the n-ZnO nanorods/p-polyfluorene （PF） structure, which was originated from the combination of the PF-related blue emission and the ZnO-related deep level emission.

Hydrothermal synthesis and characterization of two novel inorganic-organic hybrid materials

By using different organic ligands, two 3D inorganic-organic hybrid compounds Co（C4H4N2）（VO3）2 1 and Co（C12H12N2）（VO3）2 2 were synthesized by hydrothermal reaction and characterized by X-ray crystallography. Crystal data： 1. crystal system orthorhombic, space group Pnna, a=1 0.188（2） A, b=1 1.497（2） A, c=7.3975（15） A, V=866.5（3） A^3, Z=4, Dcalcd= 2.705 g/cm^3; 2. crystal system triclinic, space group P1^- （No. 2）, a=8.3190（17） A, b=8.4764（17） A, c=1 1.183（2） A, a=95.48（3）°, β=92.03（3）°, γ=107.24（3）°,V=748.0（3） A^3, Z=2, Dcalcd= 1.958 g/cm^3. The framework of compound 1 contains both {Co（C4H4N2）} and infinite metavanadate chains. Crystal structure of compound 2 is constructed with inorganic {CoV2O6} layers across-linked by organic 1,2-bis（4-pyridyl） ethane ligands. The two compounds are thermally stable to approximately 410 ℃ and 350 ℃, respectively. Their optical band gaps are determined to be 2.13 eV and 2.12 eV by UV-VIS-NIR diffuse reflectance spectra, which revealed their nature of semiconductor and optical absorption features.

Nanojunctions Contributing to High Performance Thermoelectric ZnO-Based Inorganic-Organic Hybrids

Organic-inorganic nanojunctions can result in a selective scattering of charge carrier depending on their energy, which leads to a simultaneous increase in the Seebeck coefficient S and the power factor. In this work, the nanojunction is successfully employed at the organic-inorganic semiconductor interface of polyparaphenylene （PPP） and Zn1-xAgxO nanoparticles through the sol-gel method. The presence of nanoinclusions PPP in Zno.gAgoa 0 matrix is found to be effective in improving the figure of merit （ZT） by the dual effects of an increase in the power factor consistent with the heterojunetion effect and a reduction in thermal conductivity. Zno.gAgo.10/0.1 wt% PPP exhibits a maximum figure of merit, i.e., ZT= 0.22.

Synthesis and Structure of a Novel Chain-like Inorganic-organic Hybrid Constructed from Isopolyanion and Oxalato-bridged Dinuclear Copper Complex

A novel inorganic-organic hybrid based on isopolyanion,{[Cu2（phen）2（μ-ox）][H2Mo8O26]}·4EtOH·Et2O（1） （phen=phenanthroline,ox=oxalate）,was synthesized under open-air mild reaction conditions,and characterized by elemental analysis,IR,ICP,TG and single crystal X-ray diffraction analysis.The crystal structure belongs to triclinic system with space group Pī and cell parameters：a=1.1075（5） nm,b=1.1608（5） nm,c=1.3333（5） nm,α=91.683（5）o,β=113.996（5）o,γ=112.170（5）o,V=1.4159（10） nm3,Mr=2017.44,Z=1,Dc=2.366 g/cm3 and F（000）=980.0.The structure of hybrid 1 is a 1D chain constructed of alternating octamolybdate isopolyanions [β-（Mo8O26）4-] and oxalato-bridged dinuclear copper complex cations [Cu2（phen）2（μ-ox）]2＋.Ultimately,a 3D supramolecular network was formed by hydrogen bond interactions among the adjacent chains.The result shows that hybrid 1 is the first example of inorganic-organic hybrid constructed from isopolyanion and oxalato-bridged dinuclear copper complex fragment （CCDC No.665101）.

Rare earth inorganic-organic hybrid compounds based on Keggin-type polyoxometalate {SiW_(12)} with fast-responsive photochromism and switchable luminescence properties

Four rare earth inorganic-organic hybrid compounds based on Keggin-type polyoxometalate {SiW_(12)}with general formula [{RE(DMF)_(4)(H_(2)O)_4RE(DMF)_(6)}_(2){SiW_(12)O_(40)}_(3)](RE = La(1),Pr(2),Sm(3),Eu(4),DMF=N,N-dimethylformamide) were synthesized by the conventional solution method.Structure analyses indicate that four compounds are isostructural and are all built from three [SiW_(12)O_(40)]^(4-) polyoxoanions and DMF ligands linked by RE^(3+).Compounds 1-4 are extremely sensitive to UV light and present excellent photochromic properties,in which the coloring and fading time of samples are both no more than 2 min,and the reversible coloring-fading process can be repeated for at least 10 cycles with little fatigue,suggesting that compounds 1-4 can be a series of fast-responsive and durable photochromic materials.Moreover,the solid-state photoluminescence spectra of compounds 3(Sm) and 4(Eu)display strong characteristic emissions of rare earth ions based on f-f transitions.Meanwhile,compound4(Eu) has a longer fluorescence lifetime up to 566.74 μs.Notably,co mpounds 3(Sm) and 4(Eu) exhibit the switchable luminescence behavior induced by photochromism,which allows them to be used as potential molecular switches.

Preparation and Characterization of Hybrid Aqueous Dispersions Composed of Silica Sol and Poly(styrene-co-acrylate)

A stable silica sol with 3-5 nm in diameter, which can form homogeneous film without crack, was prepared and characterized. Then, the inorganic-organic hybrid aqueous dispersion composed of such a silica sol and an emulsion of styrene （St） and acrylate （Ac） copolymer was prepared and the hybrid effect between the silica sol and poly（St-co-Ac） was observed by Fourier transform infra-red （FT-IR） spectroscope. The toughness of the film prepared by this kind of hybrid aqueous dispersion was excellent, as it was enhanced appreciably by commixing with a small amount of poly（St-co-Ac） emulsion. Some amino-polysiloxane modified hybrid aqueous dispersions were also prepared and the properties of the modified dispersions and their films were investigated. The experimental results showed that the film prepared with such an amino-polysiloxane modified hybrid dispersion exhibited excellent hydrophobicity and low surface energy after heat treatment for 1.5 h, during which the formation of the graft copolymer was observed. The surface energy of this film decreases as a result of the enrichment of siloxane segments on the film surface.

Fabrication and Luminescence of Rare Earth Complex/SiO_2 Hybrid Nanospheres

The organic rare earth complex was embedded in silica spheres to form inorganic-organic hybrid. Photoactive rare earth complexes with various organic ligands exhibit intense narrow emission band, and the silica is an excellent matrix for inorganic-organic structure. The transmission electron microscope image presents the hybrid nanospheres. The diameter of the hybrid is about 100 nm. The europium complex that incorporated into silica sphere is also proved by the IR spectra, the excitation and emission spectra. The lifetimes of the Eu 3+ ions in the hybrid nanospheres and in the pure europium complex were also detected. This hybrid with inhomogeneous compositions exhibits specifically tailored chemical and optical properties, such as perfect thermal and mechanical stability, colorimetric purity and so on. It can be used as luminescent and optical material in EL and PL fields.

Syntheses,Structures and Electrochemical Investigation of a New Dawson-based Hybrid Material with Cd-BTA Coordination Polymers

A new organic-inorganic hybrid based on tungstophosphate anions and benzotria- zole cations, [Na（BTA）E（H2O）2]2[{Cd（BTA）4（H2O）}2（P2W18O62）]·6H2O （1） （BTA = benzotriazole） has been synthesized in aqueous solution and characterized by elemental analysis, IR spectroscopy, thermal gravimetric analysis, and single-crystal X-ray diffraction. X-ray analysis showed that both {Na（BTA）2} and {Cd（BTA）4} units are supported on the a-Dawson polyoxoanion [P2W18062]6- via the surface bridging oxygen atoms. The electrochemical properties of 1 in aqueous solution are studied at room temperature. It was found that 1 presents good electrocatalytic activities for the reduction of NO2^-.

Improved performance of aluminum pigments encapsulated in hybrid inorganic-organic films

An organic silane acrylate resin （PMBK） was synthesized by free-radical solution polymerization using methyl methacrylate, butyl acrylate and （3-methacryloxypropyl）trimethoxysilane as monomers. Aluminum （AI） particles were then encapsulated in inorganic-organic hybrid films that were prepared by hydrolysis and condensation of PMBK and tetraethyl orthosilicate （TEOS） on the surface of AI pigments. Characterization results showed that PMBK and TEOS could simultaneously hydrolyze ancl condense with hydroxyl groups on the surface of the A1 particles to form composite AI particles coated with inorganic-organic hybrid films. Compared with raw AI particles, the corrosion resistance and adhesive properties of paint films containing the composite AI particles were improved greatly, while the glossiness of the paint films decreased slightly, from 48.6° to 47.0°. In alkaline media （pH 11 ）, the volume of evolved H2 of composite AI particles was only 3.5 mL, whereas that of raw AI was 83.5 mL. The glossiness of paint films containing composite A1 particles decreased by 1.66% after immersion in alkaline media for 24h, whereas that of raw AI decreased by 14.82%. Peel-off tests of the paint films showed that the composite particles moved slightly away from the paint films. In contrast, the raw A1 particles were seriously desquamated, suggesting encapsulation of hybrid films can greatly improve the adhesive properties of A1 particles in paint films.

Synthesis,crystal structure and properties of inorganic-organic hybrid polymers based on 8-hydroxylquinoline-5-sulfonic acid

Two new inorganic-organic hybrid polymers, Mn(QS)(H2O) (1) and Co(QS)(H2O)2 (2) (H2QS=8-hydroxylquinoline-5-sulfonic acid), based on 8-hydroxylquinoline-5-sulfonate ligand, have been synthesized under solvothermal conditions and their structures were solved by single-crystal X-ray diffraction analysis. Compound 1 is a three-dimensional open framework with rutile topology structure, and compound 2 is a three-dimensional supramolecular structure. These compounds were characterized by powder XRD, infrared spectroscopy, thermogravimetric analysis, fluorescence properties and magnetism properties.

Biomimetic inorganic-organic hybrid nanoparticles from magnesium-substituted amorphous calcium phosphate clusters and polyacrylic acid molecules

Amorphous calcium phosphate(ACP)has been widely found during bone and tooth biomineralization,but the meta-stability and labile nature limit further biomedical applications.The present study found that the chelation of polyacrylic acid(PAA)molecules with Ca^(2+)ions in Mg-ACP clusters(~2.1±0.5 nm)using a biomineralization strategy produced inorganic-organic Mg-ACP/PAA hybrid nanoparticles with better thermal stability.Mg-ACP/PAA hybrid nanoparticles(~24.0±4.8 nm)were pH-responsive and could be efficiently digested under weak acidic conditions(pH 5.0-5.5).The internalization of assembled Mg-ACP/PAA nanoparticles by MC3T3-E1 cells occurred through endocytosis,indicated by laser scanning confocal microscopy and cryo-soft X-ray tomography.Our results showed that cellular lipid membranes remained intact without pore formation after Mg-ACP/PAA particle penetration.The assembled Mg-ACP/PAA particles could be digested in cell lysosomes within 24 h under weak acidic conditions,thereby indicating the potential to efficiently deliver encapsulated functional molecules.Both the in vitro and in vivo results preliminarily demonstrated good biosafety of the inorganic-organic Mg-ACP/PAA hybrid nanoparticles,which may have potential for biomedical applications.

Inorganic-organic Hybrid Cathodes for Fast-charging and Long-cycling Zinc-ion Batteries

Here we report the utilization of inorganic-organic hybrid(IOH)as a new type of cathode material for aqueous Zn-ion batteries.The IOH possessing a unique lattice-water-rich layered structure achieves high long-term cycling stability(81.5%capacity retention over 1500 cycles)and ultrafast charging capability(~90%state of charge about 1 minute).