Preparation Of Novel Stable Black Phosphorus Nanosheets And Their Electrochemical Catalytic Study

The discovery and study of new materials have vital values for applications,as a well-developed material,graphene（GR）has been widely studied and applied in industry.Black phosphorus（BP）is another important material,which is the most stable allotrope of phosphorus.It displayed dramatic potentials in the applications of transistors,photocatalyst and solar cells owing to its unique anisotropic lamellar and orthorhombic crystal structure,layer-dependent bandgap,a good current on/off ratios and high room temperature mobilities.Few-layer BP nanosheets（BPNS）,obtained by mechanical exfoliation of bulk BP or by solvent exfoliation,exhibited improved electrochemical performance compared to BP,therefore,many BP-based sensors were recently developed for the detection of gases,humidity,DNA.Despite of such applications,their unavoidable instability in open air has hindered their further usage,particularly after exfoliating BP into BPNS.In this thesis,we are focusing on the improvement of stability of BPNS using the different dyes as the stabilizer.In addition,we developed the electrochemical sensors for the detection of hydrogen peroxide and dopamine（DA）using the as-prepared BPNS complex,and the resultant sensors demonstrated good performance in terms of rapidness,high sensitivity and good selectivity.These studies provide new strategies to improve the stability of BPNS and construct the corresponding electrochemical sensors,which can broaden their applications in analytical chemistry.The detailed introduction was listed below:（1）we developed a new method to prepare highly stable BPNS/TH.Thionin（TH）can automatically adsorbed on BPNS surface via theπ-πstacking interaction and stabilized the BPNS.The prepared BPNS/TH can well maintain their morphologies and exhibit good stability as long as over 1 week upon exposed to open air,which was confirmed by microscopes and spectra.The BPNS/TH modified electrode enables good electrochemical reduction of H₂O₂thanks to the intrinsic mimetic property of peroxidase property（HRP）.The H₂O₂sensor has broad linear range of 0.01–3.0 mmol·L^-1with a limit of detection（LOD）as low as 0.0134μmol?L^-1.Moreover,its good stability and repeatability were also acquired.（2）We prepared BPNS/DNR using diazotized phenazine dye（DNR）as a stabilizer,which has better stability compared to BPND/TH mentioned above.The corresponding electrochemical sensor for the detection of dopamine（DA）was also developed.The cyclic voltammetry（CV）and electrochemical impedance spectroscopy（EIS）confirmed that BPNS/DNR maintained the BPNS properties such as the large specific surface area and the abundant active sites,enabling the enrichment of target molecules.As a stabilizer and good conductive medium,it can significantly accelerate the electron transfer rate and be in favor of DA detection.The DA sensor has the linear range as broad as 0.05–75μmol?L^-1and the LOD as low as 0.077μmol?L^-1.