Preparation Of Binary Palladium - Based Materials And Study On Their Electrocatalytic Properties

Recently, the synthesis, properties study and application in various fields of electrocatalytic materials is a hot research topic, various new types of electrocatalytic materials as well as the innovation of the construction methods has been a steady stream of report. In many unique properties of electrocatalytic materials, catalytic properties have been a universal attention by researchers, while electrocatalytic materials have a wide range of applications used in electrochemical synthesis, new energy, electrochemical analysis, corrosion protection, pollution treatment, etc. In this paper, we used the liquid phase reducing method and the electrodeposition method to have the success of the preparation of palladium based electrocatalytic materials, discussed the influence in electrochemical properties of electrocatalytic materials under different conditions, and studied their applications in direct methanol fuel cell, nonenzymatic electrochemical glucose biosensor. The main work of this paper can be summarized as the following sections:Part one:the preparation of palladium based dual electric catalytic material and its research on methanol catalytic performanceWe prepared different palladium based dual electrocatalytic material using titanium plates as substrates:Pd/Ti, Pd-Ni/Ti, Pd-Co/Ti, Pd-Fe/Ti electrodes through the liquid phase reducing method, then focused on the influence of the electrocatalytic materials by changing the concentration of metal composition and reducing agent in this method, tested its electrochemical behavior in the alkaline methanol solution by using cyclic voltammetry. At last, we choosed the best liquid phase reducing conditions. For Pd-Ni/Ti electrode, when the palladium content was 95%, the current density of the oxidation peak reached maximum value 60.2 mA cm-2; For Pd-Co/Ti electrode, when the palladium content was 90%, the current density of the oxidation peak reached maximum value 69.7 mA cm-2; For Pd-Fe/Ti electrode, when the palladium content was 97%, the current density of the oxidation peak reached maximum value 82.6 mA cm-2; but the current density of the oxidation peak of the Pd/Ti electrode that has the same metal content was 46.1 mA cm-2 and the current density of the oxidation peak of the standard palladium electrode was 4.9×10-2 mA cm-2. It can be seen that the catalytic capability of palladium based dual electrode is better than the pure palladium electrode, and in the different bimetallic system, the Pd-Fe/Ti electrode had the best electrooxidation effect for methanol in alkaline medium.Part two:nonenzymatic electrochemical glucose sensor based on Pd-Fe/Ti electrocatalytic materialWe prepared Pd-Fe/Ti electrocatalytic material through the liquid phase reducing method, and a novel electrochemical glucose biosensor is constructed. Under the optimized experimental conditions, the constructed glucose sensor shows wide linear range from 2.0×10-6 to 3.0×10-3 M with a high sensitivity of 3.2×102 μA mM-1 cm-2, and the detection limit was calculated to be 1.0×10-6 M (S/N=3). The proposed glucose sensor exhibits good reproducibility, good selectivity and acceptable stability. Even more noteworthy is that it can be used in the detection of glucose in human serum sample. All the above results demonstrate Pd-Fe/Ti electrode is a great promising candidate for the fabrication of nonenzymatic electrochemical glucose sensor.Part three:nonenzymatic electrochemical glucose biosensor based on Pd-Ce electrocatalytic materialsWe synthetized the Pd-Ce electrocatalytic materials using PS spheres as the template by electrodeposition and constructed the nonenzymatic electrochemical glucose sensor. First, we droped the homogeneous dispersed PS spheres, nanoparticles electrodeposited can be highly dispersed in the gap of PS spheres and around, have very good stability and dispersion. Then loaded palladium particles on the template by electrodeposition method, finally removed the template and add 5 ul naphthol solution to get the modified Pd-Ce (PS)/GC electrode. Under the optimized experimental conditions, the constructed glucose sensor shows wide linear range from 1.0 to 14.0 mM with a high sensitivity of 2.0 μA mM-1 cm-2 and 14.0 to 47.0 mM with a high sensitivity of 1.2 μA mM-1 cm-2. Finally, we realized the high sensitivity and high selectivity of nonenzymatic glucose detection successfully, and the test based on the actual samples show that the method for real-time detection of glucose is feasible.