Microstructure of wood charcoal prepared by flash heating

Carbonized wood prepared by flash heating at 800 degreesC for I h shows a different microstructure and surface chemical structure than char formed after slow heating at 4 degreesC/min to 800 degreesC for I h. Flash heating produces pores that are surrounded by aggregates of carbon structures 25 to 100 nm in cross section. The carbon structures are built up of clearly visible graphene layers that are often curved and overlap each other in a disordered manner. The layers consist of a considerable number of oxygen-containing functional groups. The results suggest that the formation mechanism of the microstructure in wood carbonized by the flash heating process seems to originate from fragmented and oxygen-containing pyrolysis compounds in contrast to conventional heating. (C) 2003 Elsevier Ltd. All rights reserved.