Design, Synthesis And Property Research Of Novel Polyanion Borate Functional Materials

In this paper,five kinds of borate crystals were synthesized by different synthesis methods for different types of borates.And the structure of the obtained templated borate was further studied by elemental analysis,FTIR,PXRD,TG,X-ray single crystal diffraction.In this paper,not only the structure of the samples was discussed,but the properties of these compounds were also explored,such as ultraviolet,fluorescence,electrocatalysis and so on.Compound[HDBU][B₅O₆?OH?₄]?1?was obtained by solvent evaporation.The crystallographic data were as follows:triclinic,space group P 1?NO.2?,a=9.5380?7??,b=9.9420?8??,c=10.5633?7??,?=66.697?3??,?=66.457?3??,?=87.720?4??,Z=2.Compound 1 is composed of pentaborate[B₅O₆?OH?₄]^-anion and organic superbase cation[HDBU]⁺and B5 polyanion clusters form supramolecular skeleton through hydrogen bonding.Organic superbase cation[HDBU]⁺is located in the skeleton channel.Compound[HDBN][B₅O₆?OH?₄]?2?were also obtained by solvent evaporation.The crystallographic data were as follows:monoclinic,C2/m?NO.12?,a=14.329?3??,b=11.3619?19??,c=9.9036?17??,?=90.00?,?=104.129?3??,?=90.00?,Z=4.Compound 2is composed of pentaborate[B₅O₆?OH?₄]^-anion and organic superbase cation[HDBN]⁺which are different from compound 1 in organic cations,so their structure is different from that of cations filled in the skeleton of B5 anion cluster.Compound[Cd?1,2-dap?][B₆O₁₁?OH?₂]?3?was obtained by solvothermal method.The crystallographic data were as follows:triclinic,space group P-1,a=7.674?4??,b=8.179?4??,c=13.243?6??,?=102.485?9??,?=97.832?8??,?=101.510?8??,Z=8.Compound 3is a one-dimensional chain structure with B6 polyanion cluster.Under the action of hydrogen bond,the chain and chain can form a three-dimensional network through hydrogen bond.The optical properties,such as solid state ultraviolet and fluorescence,have been investigated.The band gap of the semiconductor is 4.85 eV,which can be used as broad band gap semiconductor material.Compound[Zn?NO₃?₂·8H₂O][Zn[B₆O₆?OH?₈]]·4H₂O?4?was obtained by melting low melting metal salts and then adding boric acid.The crystallographic data were as follows:monoclinic,P 21/c?14?,a=11.2817?12??,b=6.5374?7??,c=17.668?2??,?=100.98?0??,Z=2.This borate structure contains nitrate anions and boron oxide cluster anions,which are polyanionic metal borates.In addition,the optical properties were also investigated.Its band gap is about 3.53eV,so it can be used as a broad band gap semiconductor material.Compound[Zn₂BO₃][CH₃COO]?5?was synthesized by solvothermal method combined with the synthesis method of compound 4.The obtained compound 5 is also a polyanionic metal borate.The crystallographic data were as follows:orthorhombic,P 21 21 21,a=4.9500?11??,b=8.5933?19??,c=14.607?3??,?=90.00?,?=90.00?,?=90.00?,Z=4.Its structure is very distinctive.In this structure,B atom has only BO₃ coordination mode.It is a zinc borate layer in the direction of the C-axis.When we remove the B atom from it,we find a complete zinc oxide layer.A three-dimensional organic-inorganic hybrid skeleton is formed by the ligation of acetic acid molecules between layers.In addition,its optical properties were also explored.The band gap is about 4.63 eV and the thermal stability can exceed 500?.Finally,we investigate the electrocatalytic CO₂ reduction properties of the compounds.It was found that the carbon monoxide selectivity of the samples alcined at500?reached 26%.