Ion desorption is extremely challenging for adsorbents with superior performance, and widely used conventional desorption methods involve high acid or base concentrations and large consumption of reagents. Here, we experimentally demonstrate the rapid and efficient desorption of ions on magnetite-graphene oxide (M-GO) by adding low amounts of Al³⁺. The corresponding concentration of Al³⁺ used is reduced by at least a factor 250 compared to conventional desorption method. The desorption rate reaches ~97.0% for the typical radioactive and bivalent ions Co²⁺, Mn²⁺, and Sr²⁺ within ~1 min. We achieve effective enrichment of radioactive ⁶⁰Co and reduce the volume of concentrated ⁶⁰Co solution by approximately 10 times compared to the initial solution. The M-GO can be recycled and reused easily without compromising its adsorption efficiency and magnetic performance, based on the unique hydration anionic species of Al³⁺ under alkaline conditions. Density functional theory calculations show that the interaction of graphene with Al³⁺ is stronger than with divalent ions, and that the adsorption probability of Al³⁺ is superior than that of Co²⁺, Mn²⁺, and Sr²⁺ ions. This suggests that the proposed method could be used to enrich a wider range of ions in the fields of energy, biology, environmental technology, and materials science.

The two-dimensional (2D) “sandwich” structure composed of a cation plane located between two anion planes, such as anion-rich CrI₃, VS₂, VSe₂, and MnSe₂, possesses exotic magnetic and electronic structural properties and is expected to be a typical base for next-generation microelectronic, magnetic, and spintronic devices. However, only a few 2D anion-rich “sandwich” materials have been experimentally discovered and fabricated, as they are vastly limited by their conventional stoichiometric ratios and structural stability under ambient conditions. Here, we report a 2D anion-rich NaCl₂ crystal with sandwiched structure confined within graphene oxide membranes with positive surface potential. This 2D crystal has an unconventional stoichiometry, with Na:Cl ratio of approximately 1:2, resulting in a molybdenite-2H-like structure with cations positioned in the middle and anions in the outer layer. The 2D NaCl₂ crystals exhibit room-temperature ferromagnetism with clear hysteresis loops and transition temperature above 320 K. Theoretical calculations and X-ray magnetic circular dichroism (XMCD) spectra reveal the ferromagnetism originating from the spin polarization of electrons in the Cl elements of these crystals. Our research presents a simple and general approach to fabricating advanced 2D unconventional stoichiometric materials that exhibit half-metal and ferromagnetism for applications in electronics, magnetism, and spintronics.

Photocatalytic hydrogen production faces barriers to industrialization, including inadequate light absorption and limited mass/momentum transfer at scale. Integrating external hydrocyclones into photoreactors is a promising solution, yet the multiscale complexity of hydrocyclone-driven hydrogen generation impedes mechanistic understanding and rational system design. Herein, we build a scalable hydrocyclone-based photoreactor that achieves 270 mL/h hydrogen yield and 5.26% solar-to-hydrogen efficiency under simulated sunlight, as 4.5 times higher than static conditions. We develop a hierarchical multiscale model combining computational fluid dynamics, solid mechanics and density functional theory, which connects macro-scale hydrocyclone flow strain to atomic-level photocatalytic processes. Here, we show that shear stress-induced nanoscale lattice restructuring of the catalyst modulates photoexcitation pathways, triggers a threshold-activated catalytic amplification effect, and identifies an optimal flow rate of 20-30 L/min. These findings reveal a multiscale force–chemical coupling mechanism linking reactor-scale hydrocyclone flow fields to lattice-scale strain-driven catalytic enhancement, guiding large-scale photocatalytic hydrogen production.

Fe²⁺ is of considerable importance in plant growth and crop production. However, most Fe elements in nature favor existing in the trivalent state, which often causes the deficiency of Fe²⁺ in plants. Here, we report the Fe valence state change from Fe³⁺ to Fe²⁺ by using leaves. This valence state change was confirmed by x-ray photoelectron spectroscopy in Fe-Cl@leaves. Fourier transform infrared and ultraviolet-visible spectroscopy demonstrated that aromatic ring groups were included in leaves, and cation-π interactions between Fe cations and the components containing aromatic rings in leaves were measured. Further, density functional theory calculations revealed that the most stable adsorption site for hydrated Fe³⁺ cation was the region where hydroxyl groups and aromatic rings coexist. Moreover, molecular orbital and charge decomposition analysis revealed that the aromatic rings took the major part (59%) of the whole net charge transfer between leaves and Fe cations. This work provides a high-efficiency and eco-friendly way to transform the Fe valence state from Fe³⁺ to Fe²⁺, and affords a new insight into the valance change between plant organisms with cations.