Study On The Electrochemical Properties Of Pyrolysis Derivative From Metal-organic Frameworks

Due to the uniform structure and stable chemical properties,the pyrolysis derivatives based on metal-organic frameworks have attracted considerable attention in recent years,they have a good application prospect in the fields of electrochemical sensing and fuel cell.In this paper,several kinds of derivatives were successfully prepared by heating treatment,which used MOFs with controllable structure as templates,and their structures were investigated by means of various characterization.At the same time,the prepared materials were used as the sensors to electrochemical detection hydrazine hydrate and common phenolic pollutants(hydroquinone and catechol)in environment,and as the electrode materials for oxygen reduction reaction.Firstly,HKUST-1 was synthesized by solvothermal method,and used it as the precursor to obtain CuO nanomaterial,then modified it on the glassy carbon electrode,and applied to electrochemical detect hydrazine hydrate,which is a kind of highly toxic pollutants in water environment.The results showed that the response current had a good linear relationship with the hydrazine hydrate concentration in the range of 1.98-169.3?M and 232-2096 ?M,and the detection limit was low,which was 0.075 ?M(S/N = 3).The constructed sensor also showed better selectivity,and the detection results of actual water samples were also satisfactory.The method provided a reference for the rapid determination of hydrazine hydrate.Secondly,two isostructural MOFs(FJU-40-H and FJU-40-NH2)were selected to obtain two kinds of porous carbon materials:NPC-FJU-40-H and NPC-FJU-40-NH2,and the electrochemical sensors for simultaneous detection catechol and hydroquinone were constructed.The experiment showed that HQ and CT had a good response on NPC-FJU-40-H/GCE,but had no obvious response on NPC-FJU-40-NH2/GCE.The linear range of HQ and CT on NPC-FJU-40-H/GCE were 1-70 ?M and 1-100 ?M respectively,and the detection limits were 0.18 ?M and 0.31 ?M respectively,the linear range was wider and the detection limit was low.The results revealed that the differences in ligand functional groups could lead to different performances of the derived porous carbon material,which provided another way for the construction of high-performance sensors.Finally,based on compound FJU-40-H(a)and compound FJU-40-NH2(b),two core-shell structural compounds were synthesized by hetero-epitaxy,compound b@a and compound a@b.Then used a,b,b@a,a@b as templates to obtain four nitrogen-doped porous carbon materials:NPC-a-4h,NPC-b-4h,NPC-b@a-4h and NPC-a@b-4h.Their catalytic properties of oxygen reduction were also studied.The oxygen reduction catalytic results was that NPC-a@b-4h>NPC-b@a-4h>NPC-a-4h>NPC-b-4h,NPC-a@b-4h exhibited a more positive oxygen reduction potential(-0.203 V)and onset potential(-0.068 V).The results showed that the introduction of core-shell structure could promot the catalytic performance of oxygen reduction.