- 學位論文
碳氣凝膠之製備與電性分析
Studies on the Synthesis and the Electrical Characterization of Carbon Aerogel
摘要
本研究以間苯二酚（Resorcinol）及甲醛（Formaldehyde solution）做為前驅物，碳酸鈉（Sodium Carbonate）為催化劑，利用溶膠－凝膠法製備碳氣凝膠粉末，並探討改變其前驅物濃度、催化劑比例、碳化溫度和有無活化，對碳氣凝膠的結構及電性所造成之影響。 實驗製程中以熱重分析儀（TGA）分析碳氣凝膠經過高溫時裂解的變化，分出不同前驅物濃度和不同碳化溫度的樣品，以掃描式電子顯微鏡（SEM）觀察表面的形貌和表面分析儀（BET）量測其比表面積及孔洞分析；最後以四點量測（Four-Point Probe）及阻抗儀分析（LCR）測量其電性。 實驗結果在間苯二酚及甲醛摩爾比為1：2，間苯二酚及碳酸鈉的摩爾比為1000：1，並添入DI water後經過800 ℃碳化及物理活化，可得到比表面積為805.3 m2/g、平均孔洞直徑為10.2 nm，而同樣的參數但製成中不添入DI water，可得到電導率為3.8×10-3之電性最佳的碳氣凝膠。
並列摘要
In this research, the carbon aerogels were prepared by sol-gel sythesis, in which resorcinol and formaldehyde monomers were used as the precursors. Deionized water was used as the solvent. Sodium carbonate was used as the catalyst. We analyzed the influences on the structures and the electrical characteristics of the carbon aerogels by changing the parameters, including the concentrations of the precursors and the catalyst, the temperature of the carbonation process, and whether the carbon aerogels were activated or not. In our experiments, we used the Thermo Gravimetric Analysis (TGA) to observe the changes of the carbon aerogels through the pyrolysis process. Scanning Electron Microscope (SEM) was used to analyze the surface morphology. Surface Area and Pore Analysis (BET) was used to measure the specific surface and the pore characteristics. Lastly, we used the Four-Point Probe method and the Impedance Analyzer for the electrical measurements. As the result of this experiment, we have obtained the sample of the specific surface area of 805.3 m2/g and the pore diameter of 10.2 nm. In the sample, the molar ratio of resorcinol to formaldehyde (R/F) was fixed at 0.5 and the molar ratio of resorcinol to sodium carbonate (R/C) was at 1000. After added with the deionized water, the sample was treated through the carbonation at 800 ℃ and the activation. Moreover, the above parameters, but without adding the deioized water, have contributed to the highest electrical conductivity of the carbon aerogel which was 4.3×10-3 S/cm.