Novel application of imidazole-based ligand-templated borates in a zinc-air battery.

Two templated borates, [Co(1-EI)2]·[B5O7(OH)3] (1) and [Ga(1-MI)2·B6O9(OH)4]·[H3BO3]·H[1-MI] (2), have been synthesized using a mild method. Notably, they exhibit an excellent ORR performance with an E1/2 value of 0.84 V and are the first to be used as the positive electrode catalyst for a zinc-air battery, which opens a pathway for the application of borate-based oxide catalysts.

Lead-free Perovskite with Distorted [InX6]3- Octahedron Induced by Organic Cation and Enhanced PLQY by Sb Doping.

In-based halide perovskites have attracted a lot of attention because of their unique broadband emission properties. Herein, a series of In-based hybrid perovskites of (H2MP)2InCl7·H2O (1), (H2EP)2InCl7·H2O (2), (H2MP)2InBr7·H2O (3), and (H2EP)2InBr7·H2O (4) were synthesized under the control of halogen ions and organic cations. 1, 2, and 4 exhibit obvious photoluminescence properties with peaks at 392, 442, and 652 nm, respectively. The effects of the different components on the crystal structure and photoluminescence properties are discussed by calculating the structural distortion of the [InX6]3- octahedron. The photoluminescence properties of 1 and 4 were significantly improved after Sb3+ doping with PLQY values of 57.12 and 41.53%. Finally, a white LED was successfully fabricated with the two doped compounds coated onto the 365 nm blue LED chip.

Co(II)-doped hybrid Zn(II) tetraborate complexes, [ZnxCo(1-x)(1,3-dap)B4O7] (1,3-dap = 1,3-diaminopropane): BET analysis and N2/H2O/D2O adsorption studies.

A series of mono/bimetallic isostructural hybrid tetraborates of the general formula [ZnxCo(1-x)(1,3-dap)B4O7] has been prepared using a solvothermal method. Their adsorption/desorption curves for H2O and D2O demonstrate that these materials have a stronger affinity for H2O than for D2O and enrich the D2O content of D2O/H2O mixtures.

Seeking environmentally friendly halide perovskite photocatalysts: synthesis, structure and photocatalytic performance exploration.

Halide perovskites have high photoelectric conversion efficiency, making them promising candidates for photocatalysis. However, their toxic and unstable nature limits their applications. Here, we successfully synthesised three hybrid Bi-based halide perovskites: (HTMG)3Bi2Br9 (1), (HEI)2BiBr5 (2) and (HTMA)3Bi2Br9 (3). X-ray single-crystal diffraction analysis shows that they all contained 0D structures composed of isolated Bi-Br clusters. The three compounds showed excellent degradability and cycling stability for Sudan III dissolved in ethanol under simulated sunlight. In addition, the photocatalytic degradation performance of four Bi-based halide perovskites previously reported by our group is also characterised and summarised in this work.

Structural Regulation and Oxygen Reduction Reaction Activity of [Co(bpy)2BO2(OH)] and [Cu(bpy)(OH)]2- Complex Templated Borates.

Two templated borates, [Co(bpy)2BO2(OH)]·[B5O6(OH)4]·H3BO3·H3O·H2O (1) and [Cu(bpy)(OH)]2·[B5O6(OH)4]2·H2O (2), have been synthesized successfully and characterized by single-crystal X-ray diffraction, powder X-ray diffraction, and Fourier transform infrared. The [Co(bpy)2BO2(OH)] complex in 1 shows a very rare coordination mode between Co2+ and BO2(OH)2-. The structures of 1 and 2 can be adjusted by changing the reagent. The oxygen reduction reaction activity of these Co- and Cu-based catalysts was studied. The E1/2 values of Co-C-750 and Cu-C-750 are 0.864 and 0.837 V, respectively.

Exploration of the oxygen reduction reaction activity of four transition metal borates: synthesis, structure and characterization.

Four new transition metal borates, [Co(1-MI)2]·B5O7(OH)3 (1, 1-MI = 1-methylimidazole), Co2(PZ)8(SO4)2·2H3BO3 (2, PZ = pyrazole), K7{(BO3)Co[B12O18(OH)6]}·H2O (3) and K2{[Ni(PY)2]2·[(C4H2O6)2B]}2 (4, PY = pyridine), have been successfully synthesized by a mild method. Their structures were determined by X-ray single crystal diffraction. These compounds were further characterized by FTIR, PXRD and UV-vis-NIR. It is worth noting that the catalytic properties of catalysts based on these four borates were explored, and that organically templated borate 1- and 2-based catalysts showed better ORR catalytic performance compared to 3- and 4-based catalysts. This may be caused by the supramolecular skeletons of 1 and 2 providing sufficient space and porosity.

Research on the stability of luminescence of CsPbBr3 and Mn:CsPbBr3 PQDs in polar solution.

Mn:CsPbBr3 PQDs are achieved by hot injection method. As the amount of Mn doping is gradually increased, the photoluminescence (PL) spectra shows a slight blue shift. Mn-doped PQDs exhibit higher quantum efficiency of 83.9% and longer lifetimes of 267 ns. The stability test was performed to assess the susceptibility of the PQDs to polar solutions. It was figured out that although the stabilities of CsPbBr3 PQDs and Mn-doped PQDs decreased as the polarity of solution increased, Mn-doped PQDs still maintained higher PL intensity than undoped PQD. Notably, 73% PL intensity of Mn:PQDs was maintained which is nearly three times as much as undoped PQDs in water. We found polarity would induce drastic degradation of CsPbBr3 QDs. The steady-state spectroscopy, transmission electron microscopy (TEM), and X-ray diffraction (XRD) verified that CsPbBr3 QDs tend to aggregate to form larger particles under continuous light soaking. Our work reveals the main origin of instability in CsPbBr3 QDs and provides reference to engineering such QDs towards optimal device application.

Structural Characterization and ORR Activity of a Copper Complex Borate and an Unexpected [Ni(atta)(SO4)0.5]+ Borate-Sulfate.

Two metal templated borates, [Ni(atta)(SO4)0.5]·[B5O6(OH)4] (1) and [Cu(1-MI)4]·[B5O6(OH)4]2·1-MI2 (2), have been synthesized. The structures were determined by single-crystal X-ray diffraction and further characterized by Fourier transform infrared (FTIR), elemental analysis, and powder X-ray diffraction (PXRD). The structure of 1 consists of [B5O6(OH)4]- clusters and [Ni(atta)(SO4)0.5]+ complexes, which shows a very rare Ni-O-S bond. 1 and 2 exhibit a hydrogen-bonded network formed by [B5O6(OH)4]- clusters. Oxygen reduction reaction (ORR) activities of 1 and 2 were explored.

The crystal structure and oxygen reduction reaction of Ni(II)-complex templated borate-sulfate and borate.

Three nickel borate compounds, [Ni(1-MI)6]·[B(OH)3]4·SO4 (1-MI = 1-methylimidazole) (1), [Ni(H2O)3(1-MI)3]·[B5O6(OH)4]2 (2) and [Ni(DMA3)]·[B6O7(OH)6]·3.5H2O (DMA3 = N,N-dimethylethylenediamine) (3), have been synthesized. It is noteworthy that the structures of 1 and 2 can be adjusted by varying the ratio of amine. Compound 3 has shown an unexpected example of unique water clusters in its structure. The three frameworks exhibit different interlinkage modes, resulting in channels varying in their size and shape. These compounds have been characterized by FTIR, UV-vis and PXRD. In addition, 1, 2, and 3 exhibited different wide band gaps (4.4 eV for 1, 4.5 eV for 2 and 4.4 eV for 3), and ORR activities with a half-wave potential of 0.78 V for 1, 0.74 V for 2 and 0.79 V for 3.

Recent Advances in Crystalline Oxidopolyborate Complexes of d-Block or p-Block Metals: Structural Aspects, Syntheses, and Physical Properties.

Crystalline materials containing hybrid inorganic-organic metal borates (complexes with oxidoborate ligands) display a variety of novel framework building blocks. The structural aspects of these hybrid metallaoxidoborates containing Cd(II), Co(II), Cu(II), Ga(III), In(III), Mn(II), Ni(II) or Zn(II) metal centers are discussed in this review. The review describes synthetic approaches to these hybrid materials, their physical properties, their spectroscopic properties and their potential applications.

BO3 Triangle and B@Zn2O3 Cationic Layer in the Structure of the Hybrid Zinc Acetate Borate [ZnAc]·[ZnBO3].

A zinc acetate borate, [ZnAc]·[ZnBO3] (1), was synthesized under mild conditions; the B@Zn2O3 layer of 1 contains a 6-membered ring embedded with a rare BO3 unit. The layers are pillared by acetate ions to form a 3D framework. The pillared structure of 1 supplies enough space as a nanoreactor, and the related application of CO2-to-CO reduction has been confirmed.

Trinuclear Cd3O14 hexaborate and two nickel borates based on molten salt synthesis and precursor synthesis: structure, characterization, and properties.

In this work, different synthetic methods were used to prepare metal borates. One cadmium borate Cd3[B6O9(OH)2]2·2NO3·4H2O (1) and two nickel borate Ni0.8Mn0.2{B6O7(OH)3[O(CH2)2NH2]3} (2), [Ni(1-MI)6]·[B5O6(OH)4]2·2DMF (3, 1-MI = 1-methylimidazole, DMF = N,N-dimethylformamide) species were successfully prepared. The structures of these three compounds were confirmed via single crystal powder X-ray diffraction (SCPXRD), elemental analysis, FTIR, PXRD, and ICP studies. Compound 1 was prepared via molten salt synthesis, and compounds 2 and 3 were prepared via precursor synthesis, which is a synthetic method that uses a certain polyanionic cluster as a reagent. Compound 1 shows a novel three-dimensional (3D) structure, in which the [B6O11(OH)2] units acting as the basic polyanionic cluster form a two-dimensional (2D) anionic structure. In addition, the unexpected Cd3O14 clusters are connected with the 2D structures, leading to the 3D structure. The crystal structure of 2 is packed with very large neutral Ni0.8Mn0.2{B6O7(OH)3[O(CH2)2NH2]3} oxo-metal-boron clusters. The crystal structure of 3 consists of a [B5O6(OH)4]- cluster, a DMF molecule, and a [Ni(1-MI)6]2+ complex. In particular, 2 was successfully constructed using the same hexaborate cluster as its precursor. However, 3 only contains Ni2+ cations when a neutral NixMn1-x[B6O7(OH)6] cluster was used as an initial reagent, and it shows an ability to select a certain metal cation during the self-assembly process. Moreover, compounds 1, 2, and 3 exhibit different wide band gaps of 3.06 eV (1), 3.95 eV (2), and 4.24 eV (3).

A Way for Derived Carbon Materials by Thermal Etching Hybrid Borate for Electrochemical CO2 Reduction.

Two hybridized skeleton borates [Zn(en)2]·[B7O12(OH)] (1; en = ethylenediamine) and [Cd(1,3-dap)2]·[B5O8(OH)]·H2O (2; 1,3-dap = 1,3-diaminopropane) were solvothermally synthesized. The boron oxide clusters formed 2D planes, and these planes formed a 3D structure through co-oxygen links of metal complexes. Herein, a novel strategy has been developed, i.e., the derived guest carbon materials from semi-decomposed borate are incorporated into the void of host borate crystals in situ during the thermal etching process. Moreover, the effect of temperature on fluorescence of derived carbon materials was studied. By controlling the calcining temperature, carbon dots with obvious free radicals can be found via ESR technique. Carbon dots in the ethanol phase exhibited variable photoluminescence. Furthermore, it derived semi-decomposition carbon materials via thermal etching based on compounds 1 and 2. In an hydrogen cell reactor, carbon material Zn-based catalyst 1-200 catalyzes CO2 reduction to CO with a selectivity that reaches 50.8% at -1.4 V vs RHE.

Regulating the Coordination Environment of MOF-Templated Single-Atom Nickel Electrocatalysts for Boosting CO2 Reduction.

The general synthesis and control of the coordination environment of single-atom catalysts (SACs) remains a great challenge. Herein, a general host-guest cooperative protection strategy has been developed to construct SACs by introducing polypyrrole (PPy) into a bimetallic metal-organic framework. As an example, the introduction of Mg2+ in MgNi-MOF-74 extends the distance between adjacent Ni atoms; the PPy guests serve as N source to stabilize the isolated Ni atoms during pyrolysis. As a result, a series of single-atom Ni catalysts (named NiSA -Nx -C) with different N coordination numbers have been fabricated by controlling the pyrolysis temperature. Significantly, the NiSA -N2 -C catalyst, with the lowest N coordination number, achieves high CO Faradaic efficiency (98 %) and turnover frequency (1622 h-1 ), far superior to those of NiSA -N3 -C and NiSA -N4 -C, in electrocatalytic CO2 reduction. Theoretical calculations reveal that the low N coordination number of single-atom Ni sites in NiSA -N2 -C is favorable to the formation of COOH* intermediate and thus accounts for its superior activity.

Synthesis and electroluminescence of novel white fluorescence quantum dots based on a Zn-Ga-S host.

White-light-emitting Ag, Mn: Zn-Ga-S/ZnS quantum dots (QDs) with a gratifying photoluminescence (PL) quantum yield (QY) of up to 90% were prepared, and shown to be ultra-stable, maintaining a high PL intensity at 300 °C or for 32 h of UV illumination. These QDs were employed in a white QD-LED displaying a color rendering index (CRI) of 72 and maximum current efficiency of 0.22 cd A-1.

Formation Mechanism of a Polyanonic Framework from Layer to Chain Explored by Adjusting Time, Temperature, and pH: Preparation and Characterization of Metal-Complex-Templated 1D Borate and 2D Nickel Borate.

The first column of two-dimensional (2D)-layered metal-complex-templated nickel borate was obtained by using a solvothermal synthesis method. The 2D nickel borate [Ni(en)3]·[Ni0.5B6O8(OH)4]·Cl (1; en = ethylenediamine) contains [Ni(en)3]2+, Cl-, and the first reported inorganic nickel borate layer [Ni0.5B6O8(OH)4]-, which is formed by the interconnection of Ni and O atoms in the B-O cluster. By increasing the reaction temperature during the synthesis process of compound 1, the one-dimensional (1D) chain nickel borate [Ni(en)3]2·[B7O10(OH)3]·Cl2 (2) was obtained, wherein the [B7O10(OH)3] cluster was connected through an O atom to form a 1D chain structure. By adjusting the molar ratio of the raw materials, that is, adjusting the pH of the reaction, the other 1D chain nickel borate Ni(en)3·Hen·[B9O13(OH)4]·H2O (3) was obtained, in which [B5O8(OH)2] and [B4O7(OH)2] clusters can be connected via a common O atom to form an infinite [B9O13(OH)4] polyanionic chain. Meanwhile, we successfully synthesized the isoform of compound 3 with the metal cadmium.

Photoluminescent carbon dots based on a rare 3D inorganic-organic hybrid cadmium borate crystal.

A 3D inorganic-organic hybridized skeleton cadmium borate [Cden][B5O8(OH)] (1) (en = ethylenediamine) has been solvothermally synthesized. By calcining it, specific shape carbon dots (C-dots) with abundant free radicals were observed. In addition, C-dots in the ethanol phase exhibited variable photoluminescence and showed rare turn on or off effects to Cr3+ ions and CdSe/ZnS quantum dots, but only a turn on effect to Cs+ ions and a turn off effect to CsPbBr3 quantum dots.

Bright violet-to-aqua-emitting cadmium-free Ag-doped Zn-Ga-S quantum dots with high stability.

Herein, we report a new series of ultra-stable Cd-free Ag:Zn-Ga-S/ZnS quantum dots (QDs) with an overall short emission wavelength tunable from 370 to 540 nm via a facile one-pot non-injection method. The highest PL quantum yield of the resultant core/shell QDs could be up to 85%, and the exceptional luminescence could be maintained not only at 300 °C but also after phase transfer.

Photochromism, photoluminescence modulation and selective recognition of small molecules of two highly stable dynamic metal-organic frameworks.

Two highly stable dynamic metal-organic frameworks exhibit photochromism, tunable photoluminescence, and selective detection of oxygen, which can be recognised by the naked eye through color changes. Furthermore, they also display selective recognition of benzyl alcohol and halogenated solvents, respectively.

Temperature dependence of photoluminescence and hydrogen bonding revealed for the first time in a templated borate family: synthesis, structure and properties of a pentaborate [Emmim][B5O6(OH)4].

Herein, a templated borate, [Emmim][B5O6(OH)4] (denoted 1, Emmim = 1-ethyl-2,3-dimethylimidazolium), has been synthesized. It is unexpectedly observed that 1 exhibits a series of broadened luminescence curves from -183 to 75 °C, the emission intensities are measured as a decreasing function of temperature, and the line width of the PL emission is strongly enhanced when temperatures decrease below -100 °C. In addition to this, hydrogen bonding (H-B) in 1 with distinctly enlarging trends was observed as the temperature increased. The influence of temperature on H-Bs and physical properties was explored through single crystal X-ray diffraction analysis, theoretical calculations, PL, and dielectric constant test. The results indicate that the temperature can impact weak H-Bs interactions and the PL can be seen as a prober to the varying of structure such as H-Bs in borate crystal.