| Coordination Polymers(CPs)are a kind of materials with diverse structures and powerful functions that are coordinated by metal ions/metal clusters and organic compounds.They have great potential in many fields.In recent years,it received a lot of attention as a luminescence sensor and catalyst for electrocatalytic hydrogen evolution.In this paper,three zinc based coordination polymers were constructed,that is,{Zn2(bpta)2(hpta)(H2O)2·6H2O}n(1),{Zn2(bpat)2(hpta)(H2O)4·4H2O}n(2),{Zn2(bpta)(hpta)(H2O)2·2H2O}n(3),based on two similar ligands,3,5-bis(4-pyridyl)-1,2,4-triazole(bpta)and 3,5-bis(4-pyridyl)-4-amino-1,2,4-triazole(bpat).The first part of our thesis is to adjust the performance of coordination polymers according to the ligand modification strategy.We chose two ligands with similar structures(bpta=3,5-bis(4-pyridyl)-1,2,4-triazole,bpat=3,5-bis(4-pyridyl)-4-Amino-1,2,4-triazole),two zinc-based coordination polymers were synthesized by solvothermal method by introducing Zn(NO3)2·6H2O and pyromellitic anhydride(pmda):{Zn2(bpta)2(hpta)(H2O)2·6H2O}n(1),Zn2(bpat)2(hpta)(H2O)4·4H2O}n(2).During the synthesis process,pyromellitic anhydride is decomposed into pyromellitic anion(hpta4-).X-ray single crystal diffraction shows that they have similar structures,and the simplified topology is the Nb O topology type.We systematically studied their fluorescence sensing performance.The results show that they all have obvious fluorescence enhancement effects on high-valent metal ions(Fe3+?Al3+?Cr3+?In3+and Zr4+)and certain amino acids.Unlike compound 1,the change in the fluorescence properties of compound 2 is not only reflected in the intensity,but also in the position of the emission peak.In addition,2-H2O has high selectivity and sensitivity to tryptophan,and the emission peak does not move.We verified the mechanism of the difference in fluorescence response between compounds 1 and 2 by IR and X-ray photoelectron spectroscopy.The second part of the thesis is to synthesize two zinc-based coordination polymers by a one-pot method,develop an effective method through simple Co2+doping,improve and optimize the electrocatalytic performance,and obtain two kinds of high-efficiency electrocatalyst for hydrogen production by electrolysis of water.From the original compound without electrocatalytic performance to the modified low starting potential(-210m V and-240m V),ultra-high Tafel efficiency(117.7m V dec-1and 127.8 m V dec-1)and excellent cycle stability(>95%performance is retained after at least 2000 cycles).We also synthesized two isostructural Co-MOF and Ni-MOF,and found that their electrocatalytic performance was improved after the introduction of Co2+,but the effect was not as good as that of zinc-based coordination polymers.This work not only provides two excellent HER electrocatalysts,but also provides new ideas for the improvement and optimization of electrocatalytic performance. |
PDF Full Text Request