Fabrication of nitrogen doped and hierarchically porous carbon flowers for CO2 adsorption

Highly dispersed palladium nano-catalyst anchored on N-doped nanoporous carbon microspheres derived from chitosan for efficient and stable hydrogenation of quinoline

Under the background of green chemistry, the synthesis of N-heterocycles using efficient, stable and long-life catalysts has still faced great challenges. Herein, we used biomass resource chitosan to fabricate a nanoporous chitosan carbon microsphere (CCM), and successfully designed a stable and efficient Pd nano-catalyst (CCM/Pd). Various physicochemical characterizations provided convincible evidences that the palladium nanoparticles (NPs) were tightly and evenly dispersed on the CCM with a mean diameter of 2.28 nm based on the nanoporous structure and abundant functional N/O groups in CCM. Importantly, the graphitized constructure, the formed defects and larger surface area in CCM were able to promote the immobilization of Pd NPs and the electron transfer between Pd and CCM, thereby significantly improving the catalytic activity. The CCM/Pd catalyst was applied for hydrogenation of quinoline compounds, which showed excellent catalytic activity and durability, as well as good substrate applicability. The application of renewable biomass-based catalysts contributes to the progression of a green/sustainable society.

Preparation of Nitrogen-Doped Cellulose-Based Porous Carbon and Its Carbon Dioxide Adsorption Properties

Nitrogen-doped cellulose-based porous carbon materials were obtained by hydrothermal method and KOH chemical activation together with melamine as a nitrogen-doping precursor. The effects of hydrothermal temperature on the microstructure and surface morphology of the products were mainly studied. Also, the carbon dioxide adsorption capacity of the prepared porous carbon was investigated. It was found that when the hydrothermal carbonization temperature was 270 °C and the mass ratio of cellulose and melamine was 1:1, the largest micropore specific surface area of 1703 m²·g^-1 and micropore volume of 0.65 cm³·g^-1 were obtained, with a nitrogen-doping composition of 1.68 atom %. At the temperature of 25 °C and under the pressure of 0.1, 0.2, 0.3, and 0.4 MPa, the adsorption amount of CO₂ was 1.56, 3.79, 5.42, and 7.34 mmol·g^-1, respectively. Also, the adsorption process of CO₂ was in good accordance with the Freundlich isotherm model.