In this work, novel nitrogen and sulfur co-doped porous carbons were synthesized by thiourea modification of carbonized hazelnut shell, then followed by KOH activation. In current preparation protocol, thiourea acted as both N and S agent, thereby, nitrogen and sulfur were simultaneously doped into the carbon skeleton by a single-step reaction. After KOH activation, the resultant sorbents hold advanced porosity and a certain amount of N and S contents. This series of sorbents possess the highest CO₂ uptake of 4.30 and 6.44 mmol g⁻¹ at 1 bar, 25 °C and 0 °C, respectively. Comprehensive investigations found that the joint effects of narrow microporostiy, N and S content govern the CO₂ uptake of these adsorbents. Moreover, these adsorbents display various exceptional CO₂ adsorption performances such as excellent reversibility, fast CO₂ adsorption kinetics, moderate heat of adsorption, good CO₂/N₂ selectivity and high dynamic CO₂ capture capacity. Therefore, these hazelnut shell derived N, S co-doped carbons are promising in actual CO₂ capture.