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Graphical abstract Highlights • Porous carbon prepared from freeze-dried date sheets. • Porous carbon exhibits an effective pore size distribution in 0.7–0.9 nm. • Porous carbon is used as adsorbents for CO 2 in various temperature and pressure. • This work provides a practical way to develop cost-effective adsorbents. Abstract This work reports a selective chemical activation method for the controllable synthesis of porous carbons with pore sizes ranging from micropores to hierarchical micro/mesopores from date sheets. Through selectively controllable carbonization and combined activation processes, the as-prepared carbon materials exhibit a high specific surface area (3337 m2/g) mainly derived from ultra-micropores in the range of 0.7–0.9 nm, which majorly contributes to CO 2 storage at a low pressure. Among the activated carbon materials prepared, ACDS-800-4 exhibits the highest CO 2 adsorption capacity (that is, 4.36 mmol/g at 25 °C and 1 bar, and 6.4 mmol/g at 0 °C and 1 bar), a good recyclability and selectivity. ACDS-800-6 exhibits a higher CO 2 adsorption capacity of 22 mmol/g at 25 °C and a high pressure of 40 bar. This work demonstrates that the pore size is key to the CO 2 storage at lower pressures while specific surface area plays an important role under high pressure adsorption process. Since these efficient microporous carbons are synthesized from biomass, this work provides a potential way to develop cost-effective adsorbents for removing CO 2 at both low and high pressures and various temperatures. [ABSTRACT FROM AUTHOR]

[Display omitted] • Auxetic PU/PDA/GR composite foam with high EMI SE was prepared via simple method. • The relationship between EMI SE and reentrant structure was studied at first time. • The high EMI SE of auxetic foam results from the reentrant structure and high SE A. • The auxetic foam is promising as temperature-regulated EMI shielding material. In this work, two kinds of auxetic composite foams of polyurethane (PU) with polydopamine (PDA) and graphene (GR) (PU/PDA/GR) were prepared by dip-coating and ultrasonic immersing, then followed by triaxial compression-heating process. The electromagnetic interference (EMI) shielding effectiveness (SE) value of the PU/PDA/GR auxetic composite foam with a Poisson's ratio of −2.36 from PU foam with open cellular structure reaches 59.75 dB, which is 8.9 times of the positive Poisson's ratio composite foam with the same GR content. Furthermore, the relationship of the EMI shielding performance of auxetic foam with different forms of reentrant structure was studied for the first time, in which the absolute value of negative Poisson's ratio was used to quantitatively describe the difference of the reentrant structure in the obtained auxetic foam. The larger the absolute value of negative Poisson's ratio is, the better the EMI shielding performance of the composite foam is. The high absorption EMI SE and the existence of reentrant structure are the key factors for the high EMI shielding performance of the auxetic composite foam. In addition, it is found that the EMI SE of the auxetic foam can be adjusted via simple heating treatment, showing that the auxetic composite foam may be used as a temperature-regulated EMI shielding material in the future. [ABSTRACT FROM AUTHOR]