Nanomaterials

Iron-based catalysts for peroxymonosulfate (PMS) and peroxydisulfate (PDS) activation represent a cornerstone of advanced oxidation processes (AOPs) in environmental remediation, prized for their cost-effectiveness, environmental compatibility, and high catalytic potential. These catalysts, including zero-valent iron, iron oxides, and iron-organic frameworks, activate PMS/PDS through heterogeneous and homogeneous pathways to generate reactive species such as sulfate radicals (SO₄•⁻) and hydroxyl radicals (•OH). However, their large-scale implementation is constrained by inefficient iron cycling, characterized by sluggish Fe³⁺/Fe²⁺ conversion and significant iron precipitation, leading to catalyst passivation and oxidant wastage. This comprehensive review systematically dissects innovative strategies to augment iron cycling efficiency, encompassing advanced material design through elemental doping, heterostructure construction, and defect engineering; system optimization via reductant incorporation, bimetallic synergy, and pH modulation; and external field assistance using light, electricity, or ultrasound. We present a mechanistic deep-dive into these approaches, emphasizing facilitated electron transfer, suppression of iron precipitation, and precise regulation of radical versus non-radical pathways. The performance in degrading persistent organic pollutants—including antibiotics, per- and polyfluoroalkyl substances (PFASs), and pesticides—in complex environmental matrices is critically evaluated. We further discuss practical challenges related to scalability, long-term stability, and secondary environmental risks. Finally, forward-looking directions are proposed, focusing on rational catalyst design, integration of sustainable processes, and scalable implementation, thereby providing a foundational framework for developing next-generation iron-persulfate catalytic systems.

The search for high-capacity, stable anode materials is crucial for advancing lithium-ion battery (LIB) technology. Although carbon nanotubes (CNTs) are known for their excellent electrical conductivity and mechanical strength, their practical capacity is still limited. This study presents an advanced anode design by molecular functionalizing both single-walled and multi-walled carbon nanotubes (SWCNTs and MWCNTs) with tetrabromocobalt phthalocyanine (CoPc), resulting in CoPc/SWCNT and CoPc/MWCNT hybrid materials. Metal phthalocyanines (MPcs) are recognized for their tunable and redox-active properties. In CoPc, the redox-active metal centers and π-conjugated structure are uniformly attached to the CNT surface through strong π-π interactions. This synergistic combination significantly boosts the lithium-ion (Li-ion) storage capacity by offering numerous coordination sites for Li-ions and enhancing charge transfer kinetics. Electrochemical analysis shows that the CoPc-SWCNT active anode electrode material shows an impressive reversible capacity of 1216 mAh g⁻¹ after 100 cycles at a current density of 0.1 A g⁻¹, substantially surpassing the capacities of pristine CoPc (327 mAh g⁻¹) and a CoPc/MWCNT hybrid (488 mAh g⁻¹). Furthermore, the CoPc/SWCNT anode exhibited exceptional rate capability and outstanding long-term cyclability. These results underscore the effectiveness of non-covalent functionalization with SWCNTs in enhancing the electrical conductivity, structural stability, and active site utilization of CoPc, positioning CoPc/SWCNT hybrids as a highly promising anode material for high-performance Li-ion storage.

By adjusting the Cu layer thickness, this study systematically investigated the evolution of the microstructure and optoelectronic properties of WZO/Al/Cu/Al/WZO multilayer films. The results indicated that all the films exhibited a ZnO phase with hexagonal wurtzite structure and a Cu phase with face-centered cubic structure, showing preferred orientations along the (002) and (111) planes, respectively. As the Cu layer thickness increased from 5 nm to 13 nm, its crystallinity was substantially improved, with the grain size gradually increasing from 4.7 nm to 12.4 nm. In contrast, the crystalline quality of ZnO first improved and then deteriorated, reaching an optimum at a Cu layer thickness of 7 nm. With increasing the Cu layer thickness, the visible light absorption loss was enhanced and then resulted in a gradual decrease in transmittance from 79.2% to 68.0%. Benefiting from the significant improvement in the crystallinity and continuity of the Cu layer, the resistivity sharply decreased from 1.7 × 10⁻³ Ω·cm to 7.1 × 10⁻⁵ Ω·cm and tended to saturate when the thickness exceeded 9 nm. As the Cu thickness increased to 11 nm, the figure of merit (F_OM) reached a maximum value of 4.4 × 10⁻³ Ω⁻¹, demonstrating the optimal optoelectronic performance.