Synthesis,Properties And Applications Of Zinc Borate/Carbon Composites

Luminescent materials have obtained much attention in recent years due to their high practical value.Currently,the synthesis of luminescent materials based on borate matrix was generally obtained using rare earth ions as dopants.However,rare earth ion resources are scarce and expensive,and cannot be applied to large-scale industrial production.Carbon is one of the most abundant elements on the earth.The application of carbon materials in the field of luminescence is promising.Among them,carbon quantum dots graphene and carbon nanomaterials are the hottest,but their preparation methods are cumbersome and their practicality is extremely limited.Therefore,it is meaningful to look for luminescent materials with good optical performance,low cost,environmental protection and simple preparation method.For a long time,most of people neglected the optical properties of the borate matrix itself and the carbon microspheres.In this dissertation,zinc borate with stable chemical properties,good optical properties,and extremely sixpenny hydrothermal carbon microspheres were selected as the host materials to fabricate the luminescent materials.And these fluorescent composites material could be applied to the detection of Fe³⁺.There are three main parts in this paper:In the first part,a series of 4ZnO·B₂O₃·nH₂O/HTC composites were prepared by hydrothermal method,and different amounts of hydrothermal carbon microspheres?HTC?were compounded with quantitative 4ZnO·B₂O₃·H₂O.Comprehensive FTIR,XRD,SEM,PL and CIE characterizations all confirm that obtained products possess stable structures and excellent properties.The results showed that the addition of HTC component caused the gradual loss of water in4ZnO·B₂O₃·H₂O and the structures changed.The morphologies also changed from a rod-like structure to a lamellar structure,and when the molar ratio of B to C was 2:3,the carbon microspheres were more uniformly embedded in the lamellar structure,and the fluorescence intensity at this time also reached the maximum,which showed white light emission.The white light was obtained by combining the blue emission of 4ZnO·B₂O₃·H₂O(?_ex=385 nm)and the yellow emission of HTC(?_ex=414 nm),and showed a relatively pure color in CIE.In the second part,a series of 4ZnO·B₂O₃·H₂O/HTCs composites were synthesized by hydrothermal method,and different amounts of 4ZnO·B₂O₃·H₂O and quantitative hydrothermal carbon microspheres were composited.The FTIR,XRD,SEM,Mapping,XPS,PL and CIE characterizations were carried out to study their morphologies and luminescence properties.The results showed that when the molar ratio of B to C was 1:21,the composites 4ZnO·B₂O₃·H₂O/HTCs?12?was obtained.At this time,the carbon microspheres aggregated into a ring structure,and its surface was rich in oxygen-containing functional groups?-OH,-COOH etc.?,Fluorescence spectra showed that the compound displays white light emission at a wavelength of 385 nm excitation light,and the color is pure and the properties is more stable.In the third part,the 4ZnO·B₂O₃·H₂O/HTCs?12?composite was selected as the representative.The fluorescence quenching of cations by 4ZnO·B₂O₃·H₂O/HTCs?12?composite was studied by fluorescence spectrometry.The results showed that the synthesized composite 4ZnO·B₂O₃·H₂O/HTCs?12?has good selectivity for Fe³⁺ions.Within the range of 0-200?M,they have a good linear relationship?R²=0.9949?.The detection limit is 1.19?M.The quenching behavior based on Fe³⁺ions may be due to the phenolic hydroxyl groups on the surface of the composites,which conferred specific recognition of ferric ions,and caused fluorescence quenching.