Actuators based on electrically conductive and hydrophilic two-dimensional (2D) Ti₃C₂T_X MXene are of interest for fast and specific responses in demanding environments, such as chemical production. Herein, Ti₃C₂T_X-based solvent-responsive bilayer actuators were developed, featuring a gradient polymer-intercalation structure in the active layer. These actuators were assembled using negatively charged pristine Ti₃C₂T_X nanosheets as the passive layer and positively charged polymer-tethered Ti₃C₂T_X as the active layer. 2D wide-angle X-ray scattering and simulations related the gradient polymer intercalated microstructure in the polymer/MXene composite active layer to the counterintuitive actuation behavior. The bending of the bilayer films in solvent vapor is triggered by the gradient polymer-intercalation and the differing diffusion rate of solvent molecules through the MX and MX-polymer layers of the bilayer actuator. With their ease of fabrication, remote light-control capabilities, and excellent actuation performance, the Ti₃C₂T_X-based bilayer actuators reported here may find applications in areas such as sensors for monitoring chemical production, infrared camouflage, smart switches, and excavators in toxic solvent environments.

A versatile 1,2,4-triazolium-based building unit has been developed for the synthesis of porous copolymer networks, which showed potential in CO₂ capture under low-pressure conditions and CO₂ conversion. The monomer (termed [APVT]Br.HBr) combined an amino and a 1,2,4-triazolium functional group in its chemical structure and was synthesized via a quaternization reaction of 1-vinyl-1,2,4-triazole with the 3-bromopropylamine hydrobromide salt. Porous copolymer networks were obtained via solvothermal radical copolymerization of [APVT]Br.HBr with divinylbenzene (DVB) followed by neutralization to deprotonate the amine. The influence of four types of counter-anions, that is, hydroxide (OH⁻), dicyanamide (DCA⁻), ethyl sulfate, and bis(trifluoromethanesulfonyl)imide (TFSI⁻), on CO₂ capture was investigated, where copolymers bearing DCA⁻ demonstrated superior performance. Finally, the aminated 1,2,4-triazolium bromide copolymer network was subjected to catalyze the addition of CO₂ to allyl glycidyl ether into the corresponding cyclic carbonate. Our results highlight the potential of porous 1,2,4-triazolium copolymers in CO₂ capture and their valorization.

A type-III porous liquid based on zeolitic imidazolate framework-8 (ZIF-8) and an ionic liquid trihexyltetradecylphosphonium bis(trifluoromethylsulfonyl)imide ([THTDP][BTI]) was synthesized and used for the desulfurization of model diesel. The desulfurization effect by ZIF-8/[THTDP][BTI] combined both the adsorptive desulfurization by ZIF-8 and the extraction desulfurization by [THTDP][BTI]. The removal of the three chosen aromatic organic sulfides by the ZIF-8/[THTDP][BTI] porous liquid followed the order of dibenzothiophene (73.1%) > benzothiophene (70.0%) > thiophene (61.5%). It was further found that deep desulfurization could be realized by ZIF-8/[THTDP][BTI] through triple desulfurization cycles and ZIF-8/[THTDP][BTI] can be regenerated readily. The desulfurization mechanism was explored further in detail by conformation search and density functional theory calculations. Calculations supported that the large molecular volume of [THTDP][BTI] excluded itself from the cavities of ZIF-8, making the pores of ZIF-8 in the porous liquid unoccupied and accessible by other guest species, here the studied organic sulfides. These calculations indicate that the van der Waals interactions were the main interactions between ZIF-8/[THTDP][BTI] and specifically benzothiophene. This work supports that the porous liquid ZIF-8/[THTDP][BTI] could potentially be used for desulfurization of diesel in industry.

Lithium–sulfur (Li–S) battery features a high theoretical energy density, but the shuttle of soluble polysulfides between the two electrodes often results in a rapid capacity decay. Herein, a straightforward electrostatic adsorption strategy based on a cross-linked polyimidazolium separator as a snaring shield of polysulfides is reported, which suppresses the undesirable migration of polysulfides to the anode. The porous ionic network (PIN)-modified carbon nanotubes (CNTs) are successfully prepared and coated onto a commercial porous polypropylene membrane in a vacuum-filtration step. The favorable affinity of the imidazolium ring toward polysulfide via the polar interaction and the electrostatic effect of ions mitigates the undesirable shuttle of polysulfides in the electrolyte, improving the Li─S battery in terms of rate performance and cycling life. Compared to the reference PIN-free CNT-coated separator, the PIN/CNT-coated one has an increased initial capacity of 1.3 folds (up to 1394.8 mAh g⁻¹ for PIN/CNT/PP-3) at 0.1 C. 

With increasing environmental concerns due to the anthropologic emissions of greenhouse gasses, especially carbon dioxide (CO₂), the development of new technologies to capture the latter is of great public value. While amino-containing materials excel in capturing CO₂, they generally suffer from a few limitations, namely, the high energy penalty for desorption and the obstacle to directly convert CO₂ into valuable resources. In this context, molecular or polymeric compounds based on N-heterocyclic carbenes (NHCs) have emerged as versatile alternatives to efficiently sequester CO₂. NHCs are among the most investigated reactive species in chemistry: not only have they been intensively used as ligands for transition metal catalysts but also they exhibit a rich chemistry, either as true reagents or as organic catalysts. However, their air- and moisture-sensitivity represents a limitation to their use in synthesis. As reviewed thereafter, NHCs can selectively react with CO₂ forming stable adducts, in the form of zwitterionic betaine-type species, providing CO₂ directly-on-site for further fixation. Advances in the use of NHCs in this field are illustrated in this paper with a special emphasis on integration of NHCs in materials enabling heterogeneous utilizations in capture and catalysis.