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This work focuses on developing the adsorbent for carbon dioxide 1 (CO 2 ) capture from high-humidity flue gas by loading moisture-responsive 2 polyethylenimine (PEI) hydrogel interface layer in porous polymer matrix. The 3 chemical structure and porous morphology of the porous adsorbents are characterized. 4 The CO 2 adsorption capacity and adsorption thermodynamics are studied. And the 5 factors that affect the adsorption capacity including different molecular weight of PEI, 6 loading weight and crosslinking degree of hydrogel, and moisture are investigated. 7 The experimental results show that the porous polymer coated with PEI hydrogel 8 exhibits a much higher adsorption capacity for CO 2 and keep a high CO 2 -N 2 9 selectivity by effective utilization of moisture. The CO 2 adsorption capacity as high as 10 4.85mmol CO 2 /g of adsorbent is obtained at 40°C, with 1,4-butanediol diacrylate 11 (BDA)/PEI ratio of 0.25. Moreover, the formation of three-dimensional crosslinked 12 network in hydrogel shows good regeneration stability. 13

Developing a highly active and cost-effective cathode electrocatalyst with strong stability for oxygen reduction reaction (ORR) is extremely necessary. In this work, we reported a facile synthetic path to prepare a hybrid nanostructure formed of nitrogen-doped Ketjenblack carbon (N-KC) supported Co3O4 nanoparticles (Co3O4/N-KC), which could be used as a promising and stable electrocatalyst for ORR. Compared with the physical mixture of Co3O4 and N-KC and pure N-KC samples, the resulting Co3O4/N-KC nanohybrid afforded remarkably superb ORR activity with a half-wave potential of 0.82 V (vs. reversible hydrogen electrode, RHE) and a limiting current density of 5.70 mA cm−2 in KOH solution (0.1 M). Surprisingly, the Co3O4/N-KC sample possessed a similar electrocatalytic activity but better durability to the 20 wt% Pt/C catalyst. The remarkable ORR activity of the Co3O4/N-KC nanohybrid was mainly due to the strong coupling effect between Co3O4 and N-KC, the N species dopant, high electroconductivity, and the large BET surface area. Our work enlightens the exploitation of advanced Co3O4/carbon hybrid material alternative to the Pt-based electrocatalysts.

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As carbon dioxide (CO2) adsorbents, porous materials with high specific surface areas and abundant CO2-philic groups always exhibit high CO2 capacities. Based on this consensus, a category of oxygen-rich macroporous carbon foams was fabricated from macroporous resorcinol-formaldehyde resins (PRFs), which were obtained via an oil-in-water concentrated emulsion. By the active effect of potassium hydroxide (KOH) at high temperatures, the resultant carbon foams (ACRFs) possessed abundant micropores with rich oxygen content simultaneously. At the same time, most of the ACRFs could retain the marcoporous structure of their precursor. It is found that porosity of ACRFs was mainly determined by carbonization temperature, and the highest specific surface areas and total pore volume of ACRFs could reach 2046 m2/g and 0.900 cm3/g, respectively. At 273 K, ACRFs showed highest CO2 capacity as 271 mg/g at 1 bar and 91.5 mg at 15 kPa. Furthermore, it is shown that the ultra-micropore volume was mainly responsible for the CO2 capacities of ACRFs at 1 bar, and CO2 capacities at 15 kPa were mainly affected by the oxygen content. It is also found that the presence of macropores would accelerate ACRFs adsorbing CO2. This study provides ideas for designing a porous CO2 adsorbent.