| Glucose is widely used in modern life and industry as a nontoxic, inexpensive and renewable resource. Since Rao and Drake first reported the glucose oxidation on platinized-Pt electrodes in phosphate buffer solution in the1960s, electrocatalytic oxidation of glucose has been extensively investigated as a key reaction in the fields of sensors and fuel cells, etc., and exploiting electrocatalyst with high activity for glucose oxidation is of central importance in practical applications. The adsorption of glucose and its products positively affects the electrocatalytic oxidation of glucose on gold, and it is thus anticipated that the dynamic adsorption and desorption of glucose added in the Au-electroplating bath (and its electrooxidation products) on electroplating Au particles may efficiently alter the electrocatalytic activity of the Au deposits, as compared with the use of conventional glucose-free bath. Herein, we report our successful attempts on the new concept of electrodeposition of Au thin films on glassy carbon electrode (GCE) or Au electrode simply in a glucose-containing aqueous bath (Auglu) for high-performance nonenzymatic glucose sensing and glucose/O2fuel cell (FC). At the same time, rough Pt film was prepared using similar method in methanol containing plating solution for electrocatalytic oxidation of methanol and methanol fuel cell. In addition, methanol-tolerant Pt film was fabricated using similar method for catalyzing oxygen reduction. The studies in this thesis are summarized as follows:1. The Au film electrodeposited on glassy carbon or Au electrode in glucose-containing aqueous bath (Auglu) shows higher electrocatalytic activity toward glucose oxidation in neutral aqueous solution, as compared with those prepared in a conventional glucose-free bath and many previously reported analogues, and the nonenzymatic glucose sensor and glucose/O2fuel cell with outstanding performance at neutral pH are thus fabricated. The high electrocatalytic activity of Auglu is discussed from the surface area and crystal facets resulting from the dynamic adsorption-desorption of added glucose and its electrooxidation products on electroplating Au particles.2. It is well known that Pt and Pt-based metal material are the most important anode catalyst in fuel cells. We prepared highly catalytic rough Pt film using similar method in acidic solution containing methanol. For comparison, conventional electrodeposition of Pt on GCE (Ptcon/GCE) was conducted similarly in a methanol-free bath. Ptmeth/Au and Ptcon/Au electrodes were similarly prepared for EQCM studies. Comparing to conventional Ptcon/GCE, Ptmeth/GCE exhibits a high catalytic activity towards methanol electrochemical oxidation both in acidic and alkaline solutions, implying the application potential in the direct methanol fuel cell (DMFC).3. The DMFC is a promising new clean power source because methanol is an abundant and inexpensive, easily handled, transported, and stored lituid fuel with a high theoretical energy density. However, the DMFC performance is still impacted by several factors, including the poor kinetics of the oxygen reduction reaction (ORR), the high cost of the Pt-based electrocatalysts and the high methanol crossover. Thus, it is highly desirable to develop novel electrocatalysts with high ORR activity, high methanol tolerance as well as low Pt content. In this part, we obtained a novel methanol tolerant oxygen catalyst by adjusting the concentration of methanol in Pt plating solution. Compared with conventional Pt film electrode, the prepared Pt films exhibits a good ability of high methanol tolerance that conducive to be applied to construct the cathode of direct methanol fuel cell (DMFC). |
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