Transition Metals Doped Two-Dimensional Layered MolybdenumDiselenides for Electrochemical Biosensors, Biofuel Cell andSupercapacitors Applications

Autor: RAMARAJ,SUKANYA, RAMARAJ SUKANYA
Rok vydání: 2019
Druh dokumentu: 學位論文 ; thesis
Popis: 能源與光電材料專班(EOMP)
107
Recently, the layered molybdenum diselenide with 1T crystal structure has been pointed out as an efficient electrocatalyst for various electrochemical applications due to its interesting properties. Especially, the defect engineering makes the new concepts and designs to further enhance the electrocatalytic activity of layered structures. The transition metal doping on MoSe2 layered structure will create an unbalanced coulombic charge with a change in heterogeneous spin state and atomic rearrangement, which are leading to the formation of more defects/distortions with abundant active sites. Moreover, the co-occurrence of transition metals sharing their intrinsic electronic properties together and also leads to the multiple redox reactions. Encouraged by these studies, we have prepared the transition metals (M = Mn, Ni, Co and Fe) doped MoSe2 and applied as the electrode materials for bio/electrochemical sensors, biofuel cells, and supercapacitors applications. (i) Thus, we demonstrated the synthesis of Mn-doped MoSe2 and reported the resultant defective sites. The Mn doping not only helps for enzyme immobilization and also enhances the electronic conductivity of layered material. the proposed Mb immobilized MnMoSe2 (Mb@MnMoSe2) exhibited an ultra-low detection limit and higher sensitivity of H2O2. In real sample analysis, the Mb@MnMoSe2 showed a feasible recovery range for H2O2 detection in human serum, urine and water samples. On the other hand, an in-vivo study by using the living cells showed the feasible current response. (ii) The Ni doped MoSe2 nanoplate (NiMoSe2) and its application as an efficient electrocatalyst for enzymatic biofuel cell and electrochemical pseudocapacitor. The proposed enzyme immobilized bio-anode (NiMoSe2/GOD/NF) and bio-cathode (NiMoSe2/laccase/NF) exhibited better direct electron transfer behaviour between the enzymes and electrode material. Herein, the assembled biofuel cell exhibited the highest open circuit voltage and short circuit current density with the maximum power density. For electrochemical pseudocapacitor application, the proposed NiMoSe2/NF exhibited the excellent specific capacitance with excellent rate performance. (iii) The Co doped MoSe2 integrated with graphene oxide (GO) was developed to an electrode material for electrochemical sensor and supercapacitor applications. As expected, the GO@CoMoSe2 modified glassy carbon electrode exhibited an excellent electrocatalytic activity towards the sensing of metol. Thus, we concluded that the Co doping and GO hybridization with MoSe2 provide the interesting idea to find out the excellent electrocatalysts with improved electrochemical performances towards the sensing and supercapacitor applications. (iv) The Fe doped molybdenum diselenides exhibited an enhanced charge transfer conductivity and electrocatalytic activity. The electrochemical sensing of mesalamine (MES) at H-FeMoSe2/SPCE is comparatively 0.46 and 1.28 fold higher than that obtained at M-FeMoSe2/SPCE and C-FeMoSe2/SPCE respectively. Thus, H-FeMoSe2/SPCE was concluded as an excellent electrocatalyst for sensing of MES and performed DPV technique. As the results, very low detection limit of MES was achieved at H-FeMoSe2/SPCE. Hence, the selected H-FeMoSe2/SPCE was successfully subjected to the real-time detection of MES by using a paramedical tablet and reported the excellent recovery range. Thus, we concluded that the transition metal doping with MoSe2 provide the interesting idea to find out the excellent electrocatalysts with improved electrochemical performances towards the sensors, biofuel cells and supercapacitor applications.
Databáze: Networked Digital Library of Theses & Dissertations
Externí odkaz: