Vacancy-cluster-mediated surface activation for boosting CO2 chemical fixation

ScSeI Monolayer for Photocatalytic Water Splitting

We theoretically identify the ScSeI monolayer as a promising new 2D material for photocatalysis through first-principles calculations. The most notable feature is the significant difference in carrier mobility, with electron mobility in the horizontal direction being 20.66 times higher than hole mobility, minimizing electron-hole recombination. The ScSeI monolayer exhibits a bandgap of 2.51 eV, with the valence band maximum at -6.37 eV and the conduction band minimum at -3.86 eV, meeting the requirements for water splitting. Phosphorus doping lowers the Gibbs free energy by 1.63 eV, enhancing the catalytic activity. The ScSeI monolayer achieves a hydrogen production efficiency of 17%, surpassing the commercial threshold of 10% and shows excellent mechanical, thermal, and dynamic stability, indicating feasibility for experimental synthesis and practical application. Additionally, the monolayer maintains its photocatalytic properties under tensile strain (-6% to 6%) and in aqueous environments, reinforcing its potential as an effective photocatalyst. Based on these findings, we believe the ScSeI monolayer is a highly promising photocatalyst.

Non-cationic hyper-crosslinked ionic polymers with hierarchically ordered porous structures: facile synthesis and applications for highly efficient CO2 capture and conversion

Hyper-crosslinked porous ionic polymers (HCPIPs) have garnered significant attention due to their unique ionic properties and high specific surface areas. However, the limited variety of monomers, low ionic density, and difficulty in functionalization restrict their development. Herein, a series of functionalized non-cationic HCPIPs with high ionic density are designed and directly synthesized via an innovative and straightforward approach - anion (and cation) hyper-crosslinking of tetraphenylborate-based ionic liquids (ILs). These HCPIPs offer controllable hydroxyl group content (0-2.40 mmol g-1), high IL content (1.20-1.78 mmol g-1), and large specific surface area (636-729 m2 g-1) with hierarchically ordered porous structures. These HCPIPs demonstrate exceptional CO2 adsorption capacities and CO2/N2 adsorption selectivities, reaching up to 2.68-3.01 mmol g-1 and 166-237, respectively, at 273 K and 1 bar. Furthermore, these ionic porous materials serve as highly efficient heterogeneous catalysts for CO2 cycloaddition to epoxides under mild conditions (1 bar CO2, 60-80 °C, 12-24 h). Notably, the CO2 adsorption performances and catalytic activities of these HCPIPs are regulated by the hydroxyl groups within their structures, with enhancements observed as the number of hydroxyl groups increases. This work presents a facile and widely applicable method for constructing high-performance and task-specific HCPIPs.

Aqueous Electroreduction of Nitric Oxide to Ammonia at Low Concentration via Vacancy Engineered FeOCl

Electroreduction of nitric oxide (NO) to NH3 (NORR) has gained extensive attention for the sake of low carbon emission and air pollutant treatment. Unfortunately, NORR is greatly hindered by its sluggish kinetics, especially under low concentrations of NO. Herein, we developed a chlorine (Cl) vacancy strategy to overcome this limitation over FeOCl nanosheets (FeOCl-VCl ). Density functional theory (DFT) calculations revealed that the Cl vacancy resulted in defective Fe with sharp d-states characteristics in FeOCl-VCl to enhance the absorption and activation of NO. In situ X-ray absorption near-edge structure (XANES) and attenuated total reflection-infrared spectroscopy (ATR-IR) verified the lower average oxidation state of defective Fe to enhance the electron transfer for NO adsorption/activation and facilitate the generation of key NHO and NHx intermediates. As a result, the FeOCl-VCl exhibited superior NORR activities with the NH3 Faradaic efficiency up to 91.1 % while maintaining a high NH3 yield rate of 455.4 μg cm-2  h-1 under 1.0 vol % NO concentration, competitive with those of previously reported literatures under higher NO concentration. Further, the assembled Zn-NO battery utilizing FeOCl-VCl as cathode delivered a record peak power density of 6.2 mW cm-2 , offering a new route for simultaneous NO removal, NH3 production, and energy supply.