A new insight into the SO2 adsorption behavior of oxidized carbon materials using model adsorbents and DFT calculations.

Heteroatom-doped carbon materials have been proven to be very effective for gas adsorption. Herein, edge-carboxylated graphene nanoplatelets with gradient oxygen contents and consistent pore structures were used as model adsorbents to independently determine the effects of the oxygen functionalization of carbon materials on the SO2 adsorption. The OGnPs were obtained by employing a simple ball milling method using dry ice by which an oxygen content as high as 14.06 wt% could be achieved, resulting in a 20 times increase in SO2 adsorption capacity as compared to that of oxygen-free graphene nanoplatelets. Both the experiments and density functional theory calculations demonstrated that the enhanced SO2 adsorption on the oxygenated carbon surface had a physisorption nature, which provided new insights into the development of advanced carbon materials with heteroatom doping for gas molecule adsorption.

Optimizing Salt Leakage Mitigation and Comparing Sorption-Desorption Characteristics of Polyacrylamide-Based Hydrogels.

Solid hygroscopic materials are extensively utilized in diverse fields, including adsorption heat transfer, adsorption heat storage, atmospheric water harvesting (AWH), and air conditioning dehumidification. The efficacy and energy efficiency of these materials in practical applications are significantly influenced by their adsorption and desorption properties. Yet, the introduction of inorganic salts to boost adsorption performance can result in issues like salt leakage. In this research, we prepared a polyacrylamide hydrogel through free radical polymerization, and its water-absorbing capabilities were improved by incorporating the hygroscopic salt lithium chloride. We compared it to a salt-based porous adsorbent, AlFum-LiCl, which also exhibited strong water adsorption properties and the potential for large-scale production. While AlFum-LiCl suffered from limited pores and salt leakage during high water uptake, the optimized PAM-LiCl displayed superior water sorption capabilities, showing no salt leakage even at water uptake of up to 3.5 g/g. At 25 °C, PAM-LiCl achieved equilibrium water uptake of 1.26 g/g at 30% RH and 3.15 g/g at 75% RH. In this context, utilizing 20 g of PAM-LiCl for the AWH experiment yielded daily water outputs of 8.34 L/kg at 30% RH and 16.86 L/kg at 75% RH. The salt-optimized PAM-LiCl hydrogel offers the benefit of application in higher relative humidity environments without the risk of deliquescence, underscoring its promise for atmospheric water harvesting.

Tunable hybrid zeolites prepared by partial interconversion.

Zeolite interconversion is a widely used strategy due to its unique advantages in the synthesis of some zeolites. By using a long-chain quaternary amine as both a structure-directing agent and porogen, we have produced superior catalysts, which we named Hybrid Zeolites, as their structures are made of building units of different zeolite types. The properties of these materials can be conveniently tuned, and their catalytic performance can be optimized simply by stopping the interconversion at different times. For cracking the 1,3,5-triisopropylbenzene, Hybrid Zeolites made of FAU and MFI units show a 5-fold increase in selectivity towards the desired product, that is, 1,3-diisopropylbenzene, compared to the commercial FAU, and a 7-fold increase in conversion at constant selectivity compared to MFI zeolite.

Introducing catalytic gasification into chemical activation for the conversion of natural coal into hierarchically porous carbons with broadened pore size for enhanced supercapacitive utilization.

Focusing on engineering the pore structure of porous carbons for enhanced supercapacitive performances, a new type of coal derived hierarchically porous carbon which is synthesized by introducing a catalytic gasification mechanism into an often-utilized chemical activation process is demonstrated. Such a strategy skillfully employs the catalytic effects of the minerals in natural coal on the etching reaction between CO2 molecules and carbon framework, which easily widen the pore size of well-developed micropores, thereby yielding a hierarchical pore configuration with simultaneously high surface area, large pore volume as well as broadened pore size distribution. The enhanced pore development mechanism is elucidated by a series of control experiments and thermogravimetric analysis. Evaluated as supercapacitor electrode materials, the resulting HPC exhibits state-of-the-art supercapacitive performances in both aqueous and non-aqueous electrolytes, particularly the superior rate capabilities, which highlights the favorable role of broadened pore configuration in facilitating electrolyte ion transfer and storage. Combining with the naturally abundant carbon resource and easily-implemented preparation craft, the as-obtained coal transferred hierarchically porous carbons hold great potentials for industrial production and supercapacitor applications.