Shenglian Luo

High-entropy catalysts offer broad compositional tunability for peroxymonosulfate (PMS)-based water treatment, yet achieving rapid, selective, and durable oxidation remains challenging because metallic bonding in high-entropy alloys (HEAs) limits electronic communication among metal sites. Here, we construct a quinary high-entropy oxide (HEO, (FeCoNiMnCu)3O4) featuring an oxygen-bridged M-O-M framework that enables local electronic coupling among neighboring metal centers. X-ray absorption spectroscopy and theoretical calculations support oxygen-mediated charge redistribution, with Hirshfeld analysis indicating 0.46e of charge transfer toward adsorbed PMS. Temperature-dependent electrochemical impedance spectroscopy reveals a substantially lower apparent activation energy for interfacial charge transfer in the HEO (0.43 eV) than in the HEA (1.15 eV). Mechanistic experiments support a predominantly nonradical PMS activation pathway involving high-valent cobalt-oxo species and singlet oxygen. The HEO achieved near-complete phenol degradation and 87.9% total organic carbon removal within 10 min, with an apparent rate constant of 0.359 min–1 versus 0.113 min–1 for the HEA. The system maintained >90% phenol removal across pH 3–11, sustained activity over 30 reuse cycles, and retained effective contaminant removal during continuous-flow operation and 50 L bench-scale treatment. These results support lattice-oxygen-mediated electronic reconstruction as a strategy for coupling efficient PMS activation with structural durability in high-entropy oxide catalysts.

Regulating the electronic structure is critically important for direct recovering elemental valuable metals from wastewater streams. Here, a series of electronegative halogens (Cl, Br, I) are incorporated to regulate the electronic structure of Cu(I)‐based metal–organic frameworks (MOFs), enabling efficient and selective Ag(I) recovery from complex wastewater. Among them, the chlorine‐coordinated CuClMOF, featuring Cu ₂ (µ ₂ ‐Cl) motifs, exhibits excellent performance by precisely tuning the electron density of low‐valent Cu(I) sites. This electronic regulation accelerates the rate‐limiting steps of Ag(I) recovery process, shifting from conventional Ag‐halide precipitation toward a controllable and efficient reduction‐nucleation pathway. As a result, CuClMOF achieves a record‐high Ag(I) recovery capacity (1279 mg g ⁻¹ ) and rapid kinetics ( k _f ≈ 8.9 × 10 ⁻⁵ m s ⁻¹ ), while maintaining exceptional selectivity against competing ions (exceeding state‐of‐the‐art adsorbents by 1‐4 orders of magnitude). Importantly, CuClMOF maintains > 99.4% recovery in real mining wastewater and electronic waste leachates, highlighting its robustness under environmentally relevant and chemically complex conditions. The recovered silver, with a purity of 99.8%, enables direct reuse, reducing the need for primary resource extraction. By coupling high‐efficiency silver enrichment with robust adsorbent reusability, this work establishes a halogen‐mediated electronic modulation strategy for designing redox‐active adsorbents, providing a material‐level solution for silver resource recovery from complex wastewaters.

Hydroxyl radicals (•OH) possessing strong oxidizing ability serve as the core active species for the full mineralization of aromatic VOCs in photocatalysis. Enriching abundant hydroxyl groups (-OH) on catalyst surfaces is an initial step for producing abundant •OH. Herein, aluminum and iron co-modified BiOCl (AlFe-BiOCl) was synthesized to simultaneously regulate surface -OH and oxygen vacancies (OVs) that can contribute to •OH yield. Al3+ ions uniformly anchor on BiOCl as crystalline Al(OH)3, which high positivity polarize the adsorbed water and weaken O-H bonds to sustain surface -OH than can capture photogenerated holes to yield massive •OH. Simultaneously, half-filled 3d5 Fe3+ dopants replace partial closed-shell lattice Bi3+ ions in BiOCl, enabling local electron distribution and triggering lattice charge asymmetry to form OVs that further facilitate •OH production. Resultantly, the optimal, AlFe-BiOCl completely degrades 30ppm toluene within 70 min with 98% mineralization efficiency. The catalyst maintains outstanding photocatalytic activity and cycling stability under indoor conditions with 40%-80% RH and 10-50 ppm toluene. This work develops a novel strategy for synergistically regulating surface-OH and OVs of BiOCl, boosting its photocatalytic VOCs degradation performance and environmental adaptability.

Mass transfer limitations and inefficient nonradical oxidant generation often constrain the practical performance of Fenton-like catalysts for micropollutant removal. Here, we develop a synergistic architectural strategy to construct carbon-supported cobalt single-atom catalysts (Co-INC) via ammonium iodide-assisted chemical vapor deposition, integrating atomically dispersed Co–N4 sites with carbon–iodine (C–I) coordination motifs to simultaneously enhance reactant transport and singlet oxygen (1O2) production. Benefiting from in situ NH3-mediated etching, the architecture enhances active-site accessibility while achieving a high Co density of 0.165 mmol g–1, facilitating peroxymonosulfate (PMS) diffusion. Additionally, iodine incorporation creates an asymmetric Co–N4/C–I coordination environment that upshifts Co d-band center to −0.54 eV, strengthening PMS adsorption (−2.54 eV). This configuration promotes interfacial electron transfer and reduces the rate-determining energy barrier to −0.84 eV, substantially boosting 1O2 generation and achieving a steady-state concentration of 0.295 mM. Furthermore, the optimized pore architecture alleviates mass-transfer constraints, enabling efficient 1O2 utilization and a 2.3-fold increase in the ciprofloxacin mass-transfer coefficient. Consequently, Co-INC exhibits an exceptional normalized rate constant of 507 min–1·M–1 for ciprofloxacin degradation, outperforming pristine Co-NC by 10.3 times and surpassing most PMS-based catalysts. This study demonstrates that coupling active-site coordination with mass-transfer enhancement is pivotal for maximizing nonradical oxidation pathways in water treatment.

Single-atom catalysts (SACs) are among the most cutting-edge catalysts in the multiphase catalysis track due to their unique geometrical and electronic properties, the highest atom utilization efficiency, and uniform active sites. SACs have been facing an unresolved problem in practical applications: the opposing contradiction of activity-stability. The successful development of single-atom nano-islands (SANIs) cleverly combines the ultra-high atom utilization efficiency of SACs with the confinement effect and structural stability of nano-island structures, realizing the “moving but not aggregation” of SACs, which fundamentally solves this inherent contradiction. Although research on the precise loading of single atoms on nano-islands continues to advance, existing reviews have not yet established a closed-loop cognitive framework encompassing “models-synthesis-high stability mechanisms-high activity essence-applications.” This work fills this critical gap by systematically integrating the basic conceptual models and cutting-edge synthesis strategies of SANIs, focusing on revealing the underlying mechanisms by which SANIs overcome the stability bottleneck of SACs, elucidating the role of nano-islands and their synergistic mechanisms to clarify the high activity essence, and establishing the structure–activity relationship between atomic confinement effects and macroscopic performance, ultimately achieving breakthrough validation across catalytic systems. This review aims to open new perspectives, drive a paradigm shift in understanding the multi-dimensional advantages of SANIs, and thereby spur breakthrough progress in this frontier field.

Single-atom catalysts (SACs) show excellent activity and selectivity in Fenton-like reactions due to the atomically dispersed and homogeneous active sites. However, the sluggish redox kinetics of single-atom sites cause poor stability and durability. Herein, a graphitic carbon nitride-supported Fe and Cu dual-site catalyst with N₄-Fe-Cu-N₃ configuration (FeCu-CN) was designed and prepared, which promotes H₂O₂ activity through a sustainable dual-metal redox cycle and shows excellent pollutant degradation performance. The optimized FeCu-CN efficiently activates H₂O₂ to degrade sulfamethoxazole, with 23 and 4 times higher rates than Fe-CN and Cu-CN, respectively. Experimental and density functional theory (DFT) calculations indicate that the Cu site of FeCu-CN optimizes the electronic structure of Fe site and provides electrons to facilitate the Fe(III)/Fe(II) cycle. The reduction of Cu(II) by H₂O₂ and •O₂^- could promote the Cu(II)/Cu(I) cycle, maintaining the catalytic activation stability of FeCu-CN. Moreover, the synergistic effect of Fe and Cu sites in FeCu-CN promotes the adsorption of H₂O₂ and reduces the dissociation energy barrier of H₂O₂. The FeCu/H₂O₂ system exhibits strong resilience to changes in pH (from 3.18 to 9.35) and the coexisting substances. In continuous flow experiments, it also shows a long-term degradation effect on water pollutants. The FeCu-CN/H₂O₂ system has excellent anti-interference ability and application potential. This study develops a strategy for a persistent dual-metal synergistic redox cycle, providing new mechanistic insights for designing Fenton-like catalysts in efficient and environmentally friendly wastewater treatment.

Amorphous clusters are gaining prominence as prospective hosts for sodium‐ion hybrid capacitors (SIHCs), but their efficacy is still affected by atomic coordination. Optimization of ion storage and charge transport can be achieved through high coordination and bimetallic configurations. Herein, high‐coordination amorphous P ₆ ‐Nb‐W‐P ₅ (Nb/W‐P) clusters are skillfully tailored by bridging Nb into the second shell of W in the W‐P ₅ configuration, nested in situ in conductive and stable N, P co‐doped carbon nanospheres (Nb/W‐P@NPC). Such clusters with high atom utilization can offer profuse Na ⁺ storage sites due to their high coordination. As an electron donor, Nb‐bridging can subtly modify the electronic structure of clusters, and broaden the hybridization of d‐p orbitals, thus improving charge transfer efficiency and fostering diversified active sites. Compared with the low‐coordinated W‐P _L @NPC and the high‐coordinated W‐P@NPC, the reversible capacity of Nb/W‐P@NPC upgrades to 556.3 mAh g ⁻¹ at 0.1 A g ⁻¹ , alongside exceptional cycling stability at high rates. When integrated into SIHCs, the high energy density and high‐power output (223.6 and 9800 W kg ⁻¹ ) are achieved. By systematically exploring the effect of high coordination and bimetallic design on the storage efficacies of amorphous clusters, this study has greatly advanced the development of SIHC technologies.