A multi-method study of the transformation of the carbonaceous skeleton of a polymer-based nanoporous carbon along the activation pathway

作者：Hu, Cheng; Liu, Amelia C. Y.; Weyland, Matthew; Madani, S. Hadi; Pendleton, Philip; Rodriguez-Reinoso, Francisco; Kaneko, Katsumi; Biggs, Mark J.^*

来源：Carbon, 2015, 85: 119-134.

DOI：10.1016/j.carbon.2014.12.051

• HIGHLY POROUS CHARS
• KINETICALLY CONTROLLED CONDITIONS
• ENERGY-LOSS SPECTROSCOPY
• FLUCTUATION MICROSCOPY
• HEAT-TREATMENT
• COAL CHAR
• CRYSTALLINE-STRUCTURE
• ELECTRON-MICROSCOPY
• MOLECULAR-MODELS
• X-RAY

The change in the carbonaceous skeleton of nanoporous carbons during their activation has received limited attention, unlike its counterpart process in the presence of an inert atmosphere. Here we adopt a multi-method approach to elucidate this change in a poly(furfuryl alcohol)-derived carbon activated using cyclic application of oxygen saturation at 250 degrees C before its removal (with carbon) at 800 degrees C in argon. The methods used include helium pycnometry, synchrotron-based X-ray diffraction (XRD) and associated radial distribution RDF) analysis, transmission electron microscopy (TEM) and, uniquely, electron energyloss spectroscopy spectrum-imaging (EELS-SI), electron nanodiffraction and fluctuation electron microscopy (FEM). Helium pycnometry indicates the solid skeleton of the carbon densifies during activation from 78% to 93% of graphite. RDF analysis, EELS-SI, and FEM all suggest this densification comes through an in-plane growth of sp(2) carbon out to the medium range without commensurate increase in order normal to the plane. This process could be termed 'graphenization'. The exact way in which this process occurs is not clear, but TEM images of the carbon before and after activation suggest it may come through removal of the more reactive carbon, breaking constraining cross-links and creating space that allows the remaining carbon material to migrate in an annealing-like process.

• 出版日期2015-4