Synthesis, Characterization, And Electrochemistry Application Of Titanate Nanomaterials

Recent years, biosensors have been rapidly developing, and nanomaterials have been widely applied to fabricate biosensors due to their unique physical and chemical properties. In this thesis, novel electrochemical biosensors with good performance were fabricated through using inorganic layer titanate nanomaterials of unique structures. Their components, structures, sizes, shapes, and electrochemical and electrocatalytic properties were characterized by TEM, SEM, XRD, EDS, UV-vis, FT-IR, EIS, and CV. The major results of my thesis are as follows:1. Bismuth titanate (Bi4Ti3O12, BTO) and La-substituted bismuth titanate (Bi3.25La0.75Ti3O12, BLTO) nanomaterials have been successfully prepared by hydrothermal and sol-gel-hydrothermal methods, which were characterized by TEM, SEM, XRD, and EDS. Based on BTO and BLTO nanomaterials, novel electrochemical biosensors with excellent performance were acquired, and their electrochemical and electrocatalytic properties were characterized by UV-vis, FT-IR, EIS, and CV.2. Electrochemical biosensors have been prepared through using BTO nanorods (BTNRs) and nanosheets (BTNSs). UV-vis and FT-IR measurements indicate that these biosensors have good biocompabiliity; EIS and CV have demonstrated that facilitated direct electron transfer of the metalloenzymes was acquired on the BTNRs- and BTNSs-based enzyme electrodes. Comparative experiments have confirmed that the BTNSs-based biosensor has better electrochemical and electrocatalytic properties such as wider linear range (2-490μM), lower detection limit (0.28μM, S/N=3), smaller Michaelis-Menten constant (296μM) that those of the BTNRs-based biosensor.3. SEM, XRD and EDS investigations indicate that La3+ successfully substituted partial Bi ions into the BTO microspheres. BLTO microspheres were utilized to fabricate a novel biosensor by loading of myoglobin (Mb) and chitosan (Chi). UV-vis and FT-IR investigations sugust that the Mb intercalated in BLTO microspheres well retains its native structure. Compared to Mb-Chi-BTO biosensor, Mb-Chi-BLTO biosensor has better electrochemical and electrocatalytic properties such as faster direct electron transfer velocity, lower detection limit (0.14μM, S/N=3), smaller Michaelis-Menten constant (0.552 mM), and shorter response time (2.8 s).