Preparation Of Heteroatom-doped Carbon Materials And Their Application In The Detection Of Phenolic Pollutants

Hydroquinone(HQ)and catechol(CC)as two isomers of phenolic compounds,and it can be founded widely in the industrial effluents due to extensive usage in cosmetics,pesticides and pharmaceutical industries et al.However,they have been identified as one of serious environmental pollutants because of their strong toxicity and weak degradability.Therefore,a fast,sensitive and accurate method for determining HQ and CC is very important.Due to its advantages of simple operation and low cost,electrochemical methods as an important method for analysis and detection.Chemically modified electrodes have attracted the interest of researchers due to their advantages in sensitivity and selectivity.The use of carbon materials to construct the working electrode in electrochemical detection can integrate its excellent performance into the molecular operation,thereby improving the detection performance.This paper focuses on the performance of different carbon materials in electrochemical analysis and testing,and provides a theoretical basis for environmental testing.In this paper,the electrochemical performance of the modified electrode were studied by cyclic voltammetry(CV)and differential pulse voltammetry(DPV).The research content and experimental results are mainly reflected in the following two parts:(1)Detection of phenolic substances based on heteroatom-doped carbon materials.In this study,we synthesized three different catalysts,N-C,P-C and N-P-C.The results show that N-P-C has the best electrochemical detection performance.The N,P co-doped carbon(N-P-C)can be prepared with the ILs as precursors of N,P and carbon via one-pot pyrolysis,which can be used to modify the glassy carbon electrode(GCE)for simultaneous determination of hydroquinone(HQ)and catechol(CC).The obtained N-P-C was characterized by scanning electron microscopy(SEM),transmission electron microscopy(TEM),Raman spectroscopy and X-ray photoelectron spectroscopy(XPS),and electrochemical techniques.Cyclic voltammetry(CV)and differential pulse voltammetry(DPV)techniques were used to investigate the catalytic performance of simultaneous determination of HQ and CC.Under the optimized conditions,the N-P-C/GCE exhibited wide linear responses(from 5 to 400 l?M),low detection limit(0.98 ?M for HQ and 0.61 M? for CC,ratio of signal-to-noise 3)and superior sensitivity of 1.1 AM-1 cm-2 for HQ and 1.4 AM-1 cm-2 for CC in the simultaneous detection of CC and HQ,demonstrating superior detection performance even compared with the state-of-art carbon materials.Moreover,it displayed the favorable reproducibility and good long-term stability.(2)Detection of phenolic substances based on graphene-based materials.Graphene oxide was synthesis by the traditional Hummers method.The graphene can be prepared through hydrazine reduction graphene oxide.The N-doped graphene can be prepared through the mixing of urea and graphene oxide.The morphology of the three materials was preliminarily determined by scanning electron microscopy.The three materials were all in the form of a lamellar structure with a thin layer of wrinkles.The DPV test results show that graphene and its composites have a good linear relationship and excellent selectivity in the detection of hydroquinone and catechol.