Electrochemical Sensing Properties Of Hydrazine On Perylene MOFs And Its Derivatives

Hydrazine is a carcinogenic substance used in the chemical industry and exposure to hydrazine hydrate can be fatal to humans.Electrochemical detection method is considered to be the most effective detection method.Modified materials on the electrode surface can effectively improve the sensitivity and selectivity of the sensor.Metal organic frameworks（MOFs）as well as their pyrolytic derivatives are considered as materials that can be used to prepare electrochemical sensors.Therefore,the main research of this thesis is to prepare MOFs materials to study their sensing properties.By optimizing the design,hydrazine sensors with more performance are prepared.Firstly,in this paper,perylenetetracarboxylic acid of largeΠ-bonded conjugate system is chosen as the organic ligand and Co²⁺as the metal ion to prepare Co-PTC by hydrothermal synthesis reaction.on the one hand,Co-PTC is a porous material with large specific surface area,which is beneficial to the detection of hydrazine hydrate.On the other hand,the conjugated structure of perylene tetracarboxylic acid organic ligands can provide more active sites.Co-PTC was obtained by X-ray diffraction（XRD）with Materials studio software to obtain the crystal structure.The specific surface area of Co-PTC was calculated from the nitrogen adsorption-desorption isotherm of Co-PTC up to 69.7 m²/g.The Co-PTC/GCE working electrode was fabricated by drop coating method.In the electrochemical performance test of hydrazine,Co-PTC/GCE exhibited good electrochemical sensing performance with a sensitivity of 1.295μA/（m M-cm²）.The detection limit was 1μM when the signal-to-noise ratio S/N=3,and the detection range was 10-600μM.The anti-interference,stability,and repeatability of Co-PTC/GCE in the detection of hydrazine hydrate were investigated,and the experimental results showed that Co-PTC/GCE could be applied to the detection of hydrazine hydrate in practice.Secondly,the poor electrical conductivity of MOFs materials affects their electrochemical sensing performance.Based on this,Ni-PTC,which is similar to Co-PTC,was prepared by hydrothermal synthesis reaction using the product of hydrolysis of perylene anhydride as organic ligand and Ni²⁺as metal ion.Then,highly conductive porous carbon materials（TNP）were formed by pyrolysis under nitrogen atmosphere.Since the pyrolytic TNP material lost its sensitivity to hydrazine hydrate,the P-TNP material was prepared by physically encapsulating hydrazine-sensitive perylenimine molecules（PDI）into the TNP.The P-TNP/GCE working electrode was made by drop coating method.The P-TNP/GCE showed good electrochemical sensing performance in the electrochemical performance test with relatively high sensitivity[0.94μA/（m M-cm²）]and low detection limit（0.5μM）.the detection range of P-TNP/GCE was 10-900μM.