Solid sorbents with enhanced capacity and selectivity towards CO2 are crucial in the design of an efficient capture process.Among the possible alternatives,K2CO3-doped activated carbons have shown high CO2 capture capacity and rapid carbonation reaction rate.In this work,a sustainable and low-cost approach is developed with a biomass-based activated carbon or biocarbon as support.The CO2 capture performance in cyclic sorption-desorption operation and the sorption kinetics have been investigated under different scenarios in a purpose-built fixed-bed set-up.Independent of the H2O concentration in the flue gas,a constant relative humidity (～20％) in the K2CO3-doped biocarbon bed promoted the carbonation reaction and boosted the CO2 sorption capacity (1.92 mmol/g at 50℃ and 14 kPa partial pressure of CO2).Carbonation is slower than physical adsorption of CO2 but wise process design could tune the operation conditions and balance capture capacity and sorption kinetics.