Here we show that the introduction of N into a carbon surface facilitates the hydrogen-bonding interactions between the carbon surface and CO₂ molecules, which accounts for the superior CO₂ uptake of the N-doped activated carbons. This new finding challenges the long-held viewpoint that acid–base interactions between N-containing basic functional groups and acidic CO₂ gas are responsible for the enhanced CO₂ capture capacity of N-doped carbons.

Novel Fe ₃ O ₄ @Ti ₃ C ₂ MXene hybrid exhibits great promise as a high volumetric performance anode material for lithium ion batteries.

Microporous carbon materials with extremely small pore size are prepared by employing polyaniline as a carbon precursor and KOH as an activating agent. CO₂ sorption performance of the materials is systematically investigated at the temperatures of 0, 25 and 75 °C. The prepared carbons show very high CO₂ uptake of up to 1.86 and 1.39 mmol g⁻¹ under 1 bar, 75 °C and 0.15 bar, 25 °C, respectively. These values are amongst the highest CO₂ capture amounts of the known carbon materials. The relation between CO₂ uptake and pore size at different temperatures is studied. An interesting and innovative point that the micropores with pore size smaller than a critical value play a crucial role in CO₂ adsorption at different temperatures is demonstrated. It is found that the higher the sorption temperature is, the smaller this critical value of pore size is. Pores smaller than 0.54 nm are manifested to determine CO₂ capture capacity at high sorption temperature, e.g. 75 °C. This research proposes a basic principle for designing highly efficient CO₂ carbon adsorbents; that is, the adsorbents should be primarily rich in extremely small micropores.

Open carbon nanotube materials with hierarchical porosity and N-doping are prepared from polyaniline nanotubes via a combination method of pre-carbonization and post-KOH activation. The morphology, pore texture and surface properties of the carbon materials are investigated by scanning electron microscopy (SEM), transmission electron microscopy (TEM), N₂ adsorption, X-ray photoelectron spectroscopy (XPS), energy dispersive spectroscopy (EDS), Fourier transform infrared spectroscopy (FTIR) and Raman spectroscopy. The prepared carbon materials have a typical hierarchical pore texture and very high specific surface area up to 3253 m² g⁻¹. The electrochemical capacitive performance of the prepared carbons was systematically investigated in the 6 M KOH electrolyte. HPCT-4 exhibits high charge storage capacity with a specific capacitance of 365.9 F g⁻¹ at a current density of 0.1 A g⁻¹, good rate capability of 60% in the range of 0.1–10 A g⁻¹, and excellent stability over 10 000 cycles. The high capacitive performance could be due to the hierarchical porosity combined with high effective surface area and heteroatom doping effects, resulting in both electrochemical double layer and Faradaic capacitance contributions.