Production of ultra-microporous carbon from mottled bamboo pyrolysis: Multiple roles of low-dose additive CuCl2 on the product characteristics

Copper (II) chloride (CuCl₂) serve as a novel low-dose activator to produce ultra-microporous carbon during biomass catalytic pyrolysis. To understand the multiple roles of CuCl₂, a pyrolysis experiment was conducted in a fixed bed reactor at temperatures ranging from 400 to 800 °C, using CuCl₂ and mottled bamboo (MB) in a mass ratio of 0.1:1. At low temperatures of 400 °C, CuCl₂ promoted rapid precipitation of volatiles and deoxidation of fixed carbon, resulting in a decrease of the O/C ratio of carbon from 0.231 to 0.135. At high temperatures of 600∼700 °C, the bio-oil rich in ketones (83 %) and carbon material abundant in ultramicropores (72 %) were produced simultaneously. The pore expansion mechanisms were clearly analyzed: CuCl₂ promoted the expansion of mesopores, micropores (1–2 nm) and ultra-micropores (0.54 nm) through templating, dehydration at 400 °C, and etching carbon skeletons at 500–800 °C, respectively.