Importance of interaction of varied components in formation of carbon nanospheres via bio-oil pyrolysis

Abstract

Bio-oil has a high tendency towards coking upon heating, which can be the feedstock for production of carbonaceous materials with particular morpholpgy. Herein, production of carbon nanospheres via bio-oil pyrolysis at 800–1100 °C was conducted. The results revealed that the increasing temperature promoted the formation of carbon-rich structures of the nanospheres. The primary precursors for carbon spheres were identified as small gas-phase molecules. The competitive production of carbon spheres and flake carbon was observed, while carbon spheres gradually became the main product at higher pyrolysis temperature (>1000 °C). Furthermore, the abundance of aromatic organics was a critical factor for carbon nanosphere formation. Among the typical model components, the yields of carbon nanosphere at 1100 °C followed the order: guaiacol (38.2 wt%) > furfural (36.6 wt%) > heavy components (28.5 wt%). While acetic acid, acetone, and methanol as model compounds showed a yield of 0 wt%. The degree of interactions among bio-oil components also influenced the yield and properties of the produced carbon nanospheres. The addition of guaiacol to bio-oil facilitated the production of carbon spheres and graphitization, achieving a substantial yield of 12.7 wt% at 900 °C. However, the addition of methanol leads to a decrease in yield of carbon nanospheres.