Department of Materials Science and Engineering, Northwestern University , Evanston, Illinois 60208, United States.
ACS Nano. 2014 Jan 28;8(1):449-57. doi: 10.1021/nn404805p. Epub 2013 Dec 6.
Hydrothermal carbonization (HTC) of biomass such as glucose and cellulose typically produces micrometer-sized carbon spheres that are insulating. Adding a very small amount of Graphene oxide (GO) to glucose (e.g., 1:800 weight ratio) can significantly alter the morphology of its HTC product, resulting in more conductive carbon materials with higher degree of carbonization. At low mass loading level of GO, HTC treatment results in dispersed carbon platelets of tens of nanometers in thickness, while at high mass loading levels, free-standing carbon monoliths are obtained. Control experiments with other carbon materials such as graphite, carbon nanotubes, carbon black, and reduced GO show that only GO has significant effect in promoting HTC conversion, likely due to its good water processability, amphiphilicity, and two-dimensional structure that may help to template the initially carbonized materials. GO offers an additional advantage in that its graphene product can act as an in situ heating element to enable further carbonization of the HTC products very rapidly upon microwave irradiation. Similar effect of GO is also observed for the HTC treatment of cellulose.
水热碳化（HTC）生物质，如葡萄糖和纤维素，通常产生微米级的绝缘碳球。向葡萄糖中添加极少量的氧化石墨烯（GO）（例如，重量比为 1:800），可以显著改变其 HTC 产物的形态，从而得到具有更高碳化程度的更导电的碳材料。在 GO 的低质量负载水平下，HTC 处理导致数十纳米厚的分散碳片，而在高质量负载水平下，获得独立的碳块。用其他碳材料（如石墨、碳纳米管、炭黑和还原氧化石墨烯）进行的对照实验表明，只有 GO 对促进 HTC 转化有显著影响，这可能是由于其良好的水溶性、两亲性和二维结构有助于对初始碳化材料进行模板化。GO 的另一个优点是，其石墨烯产物可以作为原位加热元件，在微波辐射下使 HTC 产物非常迅速地进一步碳化。GO 对纤维素的 HTC 处理也有类似的效果。
