Investigation Of Hydrogen Peroxide Electrochemical Sensing Based On Silver Nanocomposites

Silver nanomaterials ?Ag? were widely employed in electrochemistry due to their excellent conductivity and catalytic properties. In this paper, three kinds of Ag-based nanocomposites were synthesized and three kinds of hydrogen peroxide ?H₂O₂? electrochemical sensors based on these nanocomposites were fabricated. The relationship among H₂O₂ concentrations and nanocomposites with the electrochemical performance was studied. The methods for the detection of H₂O₂ were proposed. The investigation enriched the study of electrochemical sensing and also provided reference for the application of Ag-based composites. The thesis included four chapters and the following showed the main content:1. Ag/Cu₂O nanocomposites were synthesized via chemical reduction method and the electrochemical sensor of H₂O₂ based on Ag/Cu20 was fabricated. The relationships among composition and electrocatalytic property of Ag/Cu₂O with the electrochemical response of H₂O₂ were studied. TEM showed that AgNPs were evenly distributed on the surface Cu₂O cube; The electrochemical results revealed this sensor possessed a good catalytic ability toward the reduction of H₂O₂ and offered a wide range of 2.0×10-6 mol·L-1?1.3×10-2 mol·L-1, a detection limit of 7.0×10-7 mol·L-1 ?S/N=3? and a sensitivity of 88.9 ?A ?mmol·L-1?-1 cm-2.2. Ag nanoparticles were reduced on the surface of Fe₃O₄ through the nucleation and growth processe. Ag/Fe₃O₄ nanocomposites were employed to fabricate electrochemical sensor for H₂O₂ detection. The relationships among composition and electrocatalytic property of Ag/Fe₃O₄ with the electrochemical response of H₂O₂ were studied. The results revealed that the catalytic ability of the sensor toward H₂O₂ reduction was better than that of Fe₃O₄ and Ag. The sensor offered a wide range of 5.0×10-7 mol·L-1?4.0×10-3 mol·L-1 with a low detection limit of 2.0×10-7 mol·L-1 and a sensitivity of 135.4?A ?mmol·L-1?-1 cm-2.3. Fe₃O₄@PPy/Ag nanocomposites were synthesized and then the nanocomposites were employed to fabricate the enzyme-free H₂O₂ electrochemical sensor. The relationships among composition and electrocatalytic property of Fe₃O₄@PPy/Ag with the electrochemical response of H₂O₂ were studied. The material morphology and structure were characterized by TEM. The results revealed that the material showed core-shell structure and the size of AgNPs with good dispersion was homogeneous. The electrochemical result revealed that the sensor detected H₂O₂ with a wide range of 5.0×10-6 mol·L-1 to 1.2×10-2 mol·L-1, a low detection limit of 1.7×10-6 mol·L-1 ?S/N=3? and a sensitivity of 18.2 ?A ?mmol·L-1?-1 cm-2. The study provided references for the synthesis and application of other core-shell nanocomposites.