IASS - Institute for Advanced Sustainability Studies, BerlinerStrasse 130, 14467, Potsdam, Germany.
ChemSusChem. 2013 Feb;6(2):374-82. doi: 10.1002/cssc.201200817. Epub 2013 Jan 14.
Acid pretreatment of lignocellulosic biomass, required for bioethanol production, generates large amounts of by-products, such as lignin and hydrolyzed hemicellulose fractions, which have found so far very limited applications. In this work, we demonstrate how the recovered hemicellulose hydrolysis products can be effectively utilized as a precursor for the synthesis of functional carbon materials through hydrothermal carbonization (HTC). The morphology and chemical structure of the synthesized HTC carbons are thoroughly characterized to highlight their similarities with glucose-derived HTC carbons. Furthermore, two routes for introducing porosity within the HTC carbon structure are presented: i) silica nanoparticle hard-templating, which is shown to be a viable method for the synthesis of carbonaceous hollow spheres; and ii) KOH chemical activation. The synthesized activated carbons (ACs) show an extremely high porosity (pore volume≈1.0 cm(3) g(-1)) mostly composed of micropores (90 % of total pore volume). Because of their favorable textural properties, the ACs are further tested as electrodes for supercapacitors, yielding very promising results (300 F g(-1) at 250 mA g(-1)) and confirming the high suitability of KOH-activated HTC carbons derived from spruce and corncob hydrolysis products as materials for electric double layer supercapacitors.
木质纤维素生物质的酸预处理是生物乙醇生产所必需的，会产生大量的副产品，如木质素和水解的半纤维素级分，迄今为止，这些副产品的应用非常有限。在这项工作中，我们展示了如何有效地利用回收的半纤维素水解产物作为前驱体，通过水热碳化（HTC）来合成功能性碳材料。合成的 HTC 碳的形态和化学结构得到了彻底的表征，以突出其与葡萄糖衍生的 HTC 碳的相似性。此外，还提出了两种在 HTC 碳结构中引入孔隙度的方法：i）硅纳米颗粒硬模板法，证明这是合成碳质空心球的一种可行方法；ii）KOH 化学活化法。所合成的活性炭（ACs）具有极高的孔隙率（孔体积≈1.0 cm³ g⁻¹），主要由微孔（总孔体积的 90%）组成。由于其良好的结构特性，这些 ACs 进一步被用作超级电容器的电极，结果非常有前景（在 250 mA g⁻¹时为 300 F g⁻¹），并证实了源自云杉和玉米芯水解产物的 KOH 活化 HTC 碳作为双电层超级电容器材料的高适用性。
