Polyaniline (PANI)/graphene fibers have been recognized as promising candidate for flexible electronics owing to their excellent flexible, mechanical and electrochemical properties. Their fabrication usually involved two procedures: wet spinning of graphene-based fibers with different coagulants and chemical deposition of PANI with different oxidants. Here, Fe(III) ion-mediated fabrication strategy was established as a green approach for flexible fiber supercapacitor, based on its multiple effects: coagulant in the wet spinning and catalyst in the chemical oxidation polymerization of aniline (ANI) with air, as well as the redox additive in the final fiber electrodes. As results, rEGO/Fe@PANI fiber was obtained for the flexible symmetrical fiber supercapacitor, possessing superior electrochemical performance than the reported flexible PANI/graphene fiber supercapacitors, i.e. high capacitance of 10.48 mF/cm and power density of 604.10 mW/cm at energy density of 400 μWh/cm, good capacitance retention of 90 % after 10,000 cycles and 93.1 % after extreme deformation even at 180°-folding. Such performance makes it promising candidate for the future wearable flexible electronic devices.
Trimethyl-p-benzoquinone (TMBQ) is a key intermediate in fine chemicals and vitamin E production, as global market demand steadily increasing. We can make TMBQ in a selective way from alkyl-substituted phenols by using green oxidants. This is an eco-friendly synthesis method. Nanozymes exhibiting peroxidase-like (POD-like) activity can activate peroxides to generate reactive oxygen species (ROS), thus attracting extensive attention. Of all the commonly used nanozymes, transition metal oxides are the most widely used. But their intrinsic catalytic performance still needs to be improved further. In this work, a V5+-doped hollow copper oxide nanozyme (V-CuO) was synthesized using polyoxovanadate as the vanadium source, which exhibited boosted POD-like catalytic activity. Theoretical analysis demonstrates that V doping induces lattice distortion in the Cu-O framework, leading to weakened Cu-O bonds, abundant oxygen vacancies (OVs), and an upshifted Cu 3d d-band center. As a consequence, substrate adsorption affinity is optimized and the rate-determining step (RDS) activation barrier is significantly reduced. Based on this, V-CuO efficiently catalyzes the selective oxidation of 2,3,6-trimethylphenol (TMP) to form TMBQ. These results indicate that nanozymes are promising candidates for green chemical manufacturing, and that hollow structure construction combined with heteroatom doping is an effective performance-enhancement strategy
Asymmetric hydrofunctionalization of 1,3-enynes provides an atom-economic strategy for constructing chiral unsaturated molecules. However, the simultaneous control of regioselectivity, enantioselectivity, and alkene geometry in these transformations remains challenging due to the multiple reactive sites of enynes. In addition, cascade processes that convert enynes into structurally complex chiral heterocycles remain underexplored. Herein, we report a palladium-catalyzed asymmetric annulation of phenols with 1,3-enynes through a sequential hydroarylation–hydroalkoxylation process. This transformation proceeds efficiently under additive-free conditions and displays broad substrate scope, affording enantioenriched Z-α-alkenyl-substituted 2,3-dihydrobenzofurans, which represent thermodynamically less stable alkene isomers. Mechanistic investigations suggest that the reaction proceeds through an allene intermediate and involves two interconnected Pd–H catalytic cycles. The enantioselectivity is mainly determined in the intramolecular C–O bond-forming step through a dynamic kinetic resolution process.
Photocatalytic water splitting for hydrogen (H2) production represents a vital approach for converting solar energy into chemical energy. However, the practical application of this technology is hindered by the low separation and migration efficiencies of photogenerated carriers. In this study, a compact CuCo2S4/ZnSe heterojunction was successfully fabricated using an effective electrostatic self-assembly strategy. The S-scheme charge transfer pathway between the two components was confirmed by in-situ X-ray photoelectron spectroscopy (XPS) and density functional theory (DFT) calculations, which facilitates efficient charge separation while preserving highly active electrons (e⁻) and holes (h⁺). Additionally, the formation of the heterojunction broadens the spectral response, improves the excitation and generation of photogenerated carriers, reduces charge transfer resistance, increases active sites for H+ adsorption, and accelerates the kinetics of the H2 evolution reaction (HER). As a result, the optimized 2 wt%-CuCo2S4/ZnSe achieved a H2 production rate of 89.5 mmol g-1 h-1 under visible light, which is 5.0 times higher than that of pure ZnSe, outperforming most previously reported ZnSe-based photocatalysts. This study highlights the potential of bimetallic sulfides in developing highly efficient ZnSe-based photocatalysts for solar-driven H2 production.
Sulfurized polyacrylonitrile (SPAN) is a promising cathode for the next-generation energy storage devices owing to its high specific capacity and shuttle free characteristics. However, gaining competitive energy density on battery level is still challenging for SPAN due to its relatively low discharge potential, which makes the study on high loading (areal capacity) electrodes quite essential. Herein, a mechanical enhanced binder with high ionic conductivity is constructed by grafting ferrocene on polyethylenimine (PEI-Fc) and crosslinking it with β-cyclodextrin polymer (β-CDp). The binder imparts high mechanical strength originating from the hydrogen bond and supramolecular interactions between the guest groups Fc and the cavitand host of β-CD, enabling the effective stress dissipation and maintaining a stable electrode/electrolyte interphase during cycling. In addition, a fast lithium transport channel for facilitating Li+ diffusion in the SPAN electrode is constructed by the cavities of the cyclodextrin and the lithiophilic ferrocene moieties. As a result, the SPAN||Li battery with 5 % β-CDp/PEI-Fc binder exhibits impressive cycling performance under 19.8 mg/cm2 SPAN loading and 3.0 μL/mg lean electrolyte conditions. This work provides a creative strategy for designing functional binders for high performance lithium-sulfur batteries with high loading mass.
Identification of ischemic stroke during hyperacute phase is crucial for subsequent treatment decisions and patient prognosis. However, existing diagnostic techniques, such as magnetic resonance imaging (MRI), still face limitations, including a relatively delayed detection window and high examination costs, making it difficult to fully meet the clinical demand for rapid identification during the hyperacute phase. Optical molecular imaging based on abnormal changes in stroke-related endogenous metabolites provides a new approach for earlier lesion identification. Hydrogen polysulfides (H2Sn) and formaldehyde (FA) are two key metabolites that are synergistically elevated during the process of ischemic stroke, serving as potential dual targets for molecular imaging in the hyperacute phase. In this work, we obtained an H2Sn/FA cascade-responsive two-photon fluorescent probe, H2Sn-FA, which can sequentially recognize H2Sn and FA to trigger a cascade “turn-on” signal amplification, thereby improving the recognition specificity and imaging sensitivity in complex biological environments. Experimental results demonstrate that H2Sn-FA exhibits excellent selectivity and sensitivity toward the target molecules, along with low cytotoxicity. In a mouse model of ischemic stroke, H2Sn-FA enabled in vivo fluorescence imaging within 15 min, while MRI required up to 30 min to obtain an identifiable signal, saving 15 min for treatment decision. Furthermore, the probe allowed for the dynamic monitoring of secondary injury in the contralateral cerebral hemisphere induced by ischemia-reperfusion. This study establishes a H2Sn/FA cascade response strategy for hyperacute imaging of ischemic stroke; providing a potential tool for rapid molecular identification of stroke and laying a foundation for future clinical translation.
Although zinc-air batteries (ZABs) are considered promising energy storage technologies due to their high energy density and low cost, their efficiency and durability are severely limited by the sluggish kinetics of the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER). Hence, an atomic-level electronic reconstruction strategy is proposed, in which atomically dispersed Co and Fe bimetallic sites are anchored on α-MnO2 nanorods (Co-Fe@MnO2), thereby enabling highly reversible and durable electrocatalysis. The strong electronic interactions between Co-Fe dual sites and the MnO2 support induce the generation of abundant low-valence Mn species and oxygen vacancies, enriching electronic states near the Fermi level and downshifting the d-band center. This dual-site-induced electronic reconstruction optimizes the adsorption and desorption of oxygen intermediates, effectively accelerating the kinetic processes of ORR and OER. Therefore, the Co-Fe@MnO2 catalyst delivers outstanding bifunctional electrocatalytic activity, with a half-wave potential of 0.85 V for the ORR, and an overpotential of 230 mV for the OER at 10 mA/cm2, yielding a narrow bifunctional potential gap of 0.83 V. Consequently, the self-assembled rechargeable ZAB integrated with the Co-Fe@MnO2 air cathode achieves a peak power density of 249 mW/cm2 at 360 mA/cm2 and exhibits excellent cycling stability. This study reveals the key role of dual-site-induced electronic reconstruction in regulating the catalytic behavior of MnO2 and provides a practical strategy for designing high-performance bifunctional electrocatalysts for metal-air energy storage systems.
Asymmetric energy transfer (EnT) photocatalysis faces a critical challenge: the spatial segregation between photosensitizer and substrate imposed by chiral catalysts severely restricts EnT efficiency. The Tan group has recently developed a relay energy transfer strategy based on CETA (Chiral EnT Acid) catalysts, which integrate an energy carrier, a catalytic center, and a stereogenic element into a single scaffold. Applied to the dearomative [4+2] cycloaddition of quinolines with alkenes, the CETA catalyst overcomes the EnT barrier, achieving a threefold improvement in energy transfer efficiency and extending the excited-state lifetime of the substrate via reversible energy storage. This work establishes a new paradigm for asymmetric EnT photocatalysis and offers a blueprint for designing chiral catalysts with enhanced energy-transfer capability.
Photocatalytic O2 activation involving charge carriers offers a sustainable approach for wastewater decontamination. However, its efficiency is often hampered by insufficient charge separation and inadequate O-O bond activation. Herein, we demonstrate that constructing monatomic manganese and oxygen vacancy dual sites (Mn1-VO) on the BiOCl surface enables homolytic O2 dissociation into atomic reactive oxygen species (•O−). The strategically introduced Mn1 site facilitates robust exciton dissociation into charge carriers. Coupled with the adjacent VO, it switches the O2 adsorption configuration from an end-on to a side-on bridging mode, stretching the O-O bond from 1.22 Å to 3.04 Å and promoting its barrierless cleavage into •O−. In the photodegradation of nitrogen-containing heterocyclic aromatic contaminants (NHACs), •O− preferentially attacks the unsaturated alkene double bonds or C-N bonds within the heterocycles, leading to deconjugated oxidation and subsequent ring-opening mineralization. Remarkably, BiOCl with Mn1-VO dual sites exhibit superior photoactivity for degrading refractory NHACs with conjugated multi-membered rings, such as carbamazepine, sulfadimidine, sulfamethoxazole, and norfloxacin, outperforming counterparts with only Mn1 or VO sites. This work highlights the crucial role of metal-oxygen vacancy dual sites in modulating O2 activation for solar-driven wastewater purification.
Room-temperature sodium–sulfur batteries (RT-NSBs) are promising for large-scale energy storage; however, their practical implementation is impeded by polysulfide dissolution/shuttling, sluggish sulfur redox kinetics, and the insulating nature of sulfur species. Electrocatalyst engineering has emerged as an effective strategy to regulate polysulfide adsorption, accelerate conversion reactions, and improve sulfur utilization. In this review, we systematically summarize recent advances in carbon-based electrocatalysts for RT-NSBs, with emphasis on the fundamental design principles governing catalyst structure, electronic properties, active sites, and catalytic performance. The relationships between catalyst characteristics and key sulfur redox processes, including polysulfide immobilization, diffusion, and conversion, are systematically discussed. Finally, remaining challenges and future perspectives toward rational catalyst design and practical applications are highlighted.
To overcome the non-selective nature of conventional periodate (PI) activation and the intrinsic passivation of traditional zero-valent iron (ZVI), this study rationally designed a lignin sulfonate-modified ZVI (LS-ZVIbm) composite via mechanochemical synthesis to sustain the effective activation of PI for sulfamethazine (SMT) degradation. The tailored LS-ZVIbm/PI system achieved a remarkable SMT removal efficiency of 96.3 % within 5 min, whereas the unmodified ZVIbm/PI system exhibited a negligible removal of 3.7 %. Notably, the pseudo-first-order rate constant for the modified system was enhanced by over 170-fold, allowing for a reduction in both catalyst and oxidant dosages by more than 90 %. Comprehensive characterizations revealed that the electron-rich sulfonate groups (-SO3H) of LS acted as an endogenous electron shuttle, which significantly accelerated the interfacial Fe(III)/Fe(II) redox cycle and ensured a continuous supply of reactive Fe(II). Crucially, synchrotron X-ray absorption fine structure (XAFS) spectroscopy rigorously confirmed the unique Fe-S coordination microenvironment. Combined with in-situ analyses and density functional theory (DFT) calculations, the structure-activity relationship was fundamentally elucidated. The uniquely constructed Fe-S coordination microenvironment engineered the local electronic structure, facilitating the targeted injection of electrons specifically into the I-O antibonding orbital of the adsorbed PI. This localized charge transfer profoundly altered the reaction energetics (yielding a highly exergonic relative free energy, ∆G = -3.72 eV), thermodynamically favoring the specific homolytic cleavage of the I-O bond. Consequently, this robust interfacial activation successfully sustained a highly selective, iodate radical (IO3•)-dominated degradation network, as corroborated by in-situ Fourier transform infrared spectroscopy (FTIR) and comprehensive quenching analyses. Finally, toxicity assessments confirmed that this sustained IO3•-driven process efficiently deconstructed SMT into intermediates with significantly diminished overall ecotoxicity, completely precluding the formation of hazardous iodinated byproducts. This work provided a rigorous proof-of-concept for engineering interfacial microenvironments to thermodynamically sustain key reactive species in environmental remediation.
