Phiri Josphat, Ahadian Hamidreza, Sandberg Maria, Granström Karin, Maloney Thad
School of Chemical Engineering, Department of Bioproducts and Biosystems, Aalto University, P.O. Box 16300, 00076 Aalto, Finland.
Department of Engineering and Chemical Sciences, Karlstad University, 651 88 Karlstad, Sweden.
Micromachines (Basel). 2023 Feb 28;14(3):572. doi: 10.3390/mi14030572.
In this study, two different sample preparation methods to synthesize activated carbon from pine wood were compared. The pine wood activated carbon was prepared by mixing ZnCl by physical mixing, i.e., "dry mixing" and impregnation, i.e., "wet mixing" before high temperature carbonization. The influence of these methods on the physicochemical properties of activated carbons was examined. The activated carbon was analyzed using nitrogen sorption (surface area, pore volume and pore size distribution), XPS, density, Raman spectroscopy, and electrochemistry. Physical mixing led to a slightly higher density carbon (1.83 g/cm) than wet impregnation (1.78 g/cm). Raman spectroscopy analysis also showed that impregnation led to activated carbon with a much higher degree of defects than physical mixing, i.e., / = 0.86 and 0.89, respectively. The wet impregnated samples also had better overall textural properties. For example, for samples activated with 1:1 ratio, the total pore volume was 0.664 vs. 0.637 cm/g and the surface area was 1191 vs. 1263 m/g for dry and wet mixed samples, respectively. In the electrochemical application, specifically in supercapacitors, impregnated samples showed a much better capacitance at low current densities, i.e., 247 vs. 146 F/g at the current density of 0.1 A/g. However, the physically mixed samples were more stable after 5000 cycles: 97.8% versus 94.4% capacitance retention for the wet impregnated samples.
在本研究中，比较了两种用松木合成活性炭的不同样品制备方法。通过物理混合（即“干混”）和浸渍（即“湿混”）ZnCl₂，然后进行高温碳化来制备松木活性炭。研究了这些方法对活性炭物理化学性质的影响。使用氮吸附（表面积、孔体积和孔径分布）、XPS、密度、拉曼光谱和电化学对活性炭进行了分析。物理混合得到的碳密度（1.83 g/cm³）略高于湿浸渍法得到的碳（1.78 g/cm³）。拉曼光谱分析还表明，浸渍法得到的活性炭缺陷程度比物理混合法高得多，即分别为 /= 0.86 和 0.89。湿浸渍样品的整体结构性质也更好。例如，对于以 1:1 比例活化的样品，干混和湿混样品的总孔体积分别为 0.664 和 0.637 cm³/g，表面积分别为 1191 和 1263 m²/g。在电化学应用中，特别是在超级电容器中，浸渍样品在低电流密度下表现出更好的电容，即在 0.1 A/g 的电流密度下为 247 对 146 F/g。然而，物理混合样品在 5000 次循环后更稳定：湿浸渍样品的电容保持率为 94.4%，而物理混合样品为 97.8%。
