ACS Applied Nano Materials最新文献

Hematite (α-Fe₂O₃) has a high theoretical photocurrent but has not achieved much due to its sluggish water oxidation kinetics and severe charge recombination. In the present work, gradient Cu and S doping was introduced into Ti-doped Fe₂O₃ (Ti:Fe₂O₃) through a high-temperature diffusion process at 450 °C from the doping source of CuSO₄. The Ti-, Cu-, and S-doped Cu@Ti:Fe₂O₃ photoanode, without cocatalyst modification, obtains a high photocurrent density of 1.81 mA cm^–2 at 1.23 V_RHE under AM 1.5G illumination. Compared with Fe₂O₃, the onset potential of Cu@Ti:Fe₂O₃ shifts significantly negatively by around 520 mV. The improvement should be mainly attributed to the formed p–n homojunction, which can provide extra energy for the separation of charges that are generated by light. Interestingly, the photocurrent density can increase gradually during the stability test under illumination and reach a photocurrent density of 2.45 mA cm^–2 after 10 h. This can be ascribed to surface dissolution of the Cu@Ti:Fe₂O₃ photoanode, which induces more active sites and obvious characteristics of the p–n homojunction.

The enhancement of energy storage capabilities in metal hydroxides relies on the improvement of their intrinsic conductivity and structural stability. In this study, we propose an approach to tackle these challenges by incorporating structural doping with magnesium and compositing with carbon nanotubes (CNTs) through a mechanochemical method. Initially, CNTs are mixed with magnesium acetate (Mg(Ac)₂) to form a CNT/Mg(Ac)₂ mixture, which is then annealed to yield a CNT/MgO mixture. Subsequent ion-exchange reaction at room temperature transforms the magnesium oxide component into CoNi LDH, leveraging the differences in solubility product constants (K_sp) between magnesium hydroxide and nickel cobalt hydroxides. The resultant CNT/CoNi LDH composite displays a nanosheet morphology and uniform distribution of components facilitated by the CNT compositing. As an electrode material for asymmetric supercapacitor energy storage, the CNT/CoNi LDH1–10 exhibits enhanced energy storage performance relative to pristine CoNi LDH, with increased capacitance in both three-electrode and asymmetric configurations as well as higher energy density. Additionally, the structural doping confers exceptional cycling stability to the CNT/CoNi LDH1–10, maintaining nearly 100% capacitance retention after 90,000 charge/discharge cycles. This study introduces a versatile approach for fabricating doped and composited CoNi LDH materials and their mixed oxide counterparts with potential applications in catalysis, energy storage, and other domains.

Two-dimensional single-crystal nanomaterials have been extensively studied in various fields due to their unique structure and crystalline properties. However, chemical synthesis methods have limitations in precisely controlling the crystal assembly structure. The inevitable stacking phenomenon in two-dimensional (2D) nanomaterials hinders the full utilization of advantages of highly exposed surfaces, thereby restricting the developmental potential in this field. In this work, we report a polyacid-induced solvothermal method for constructing highly (101)-exposed hierarchical single-crystal titanium dioxide (HSC-TiO₂) with a thickness of 25 nm and an average size of 2 μm in the anatase phase. By adjusting the mixed acid ratio and reaction time, the constituent units from 0D to 2D and the number of layers can be further modulated while maintaining crystal orientation. Such a combination of crystalline orientation and hierarchical spatial structure provides efficient mass and charge transfer that greatly promotes the hydrogen generation rate under sunlight with good stability. The study is envisaged to afford an exciting pathway for the design and synthesis of specific single-crystal structures, nanoarchitectures, and complex hierarchies toward future nanotechnologies.

Conversion-type iron oxide (FeO_x) anodes for lithium-ion batteries (LIBs) face critical practical challenges, including large voltage hysteresis, severe electrode degradation, and active material pulverization. To overcome these limitations, we develop a carbon-encapsulated amorphous FeO_x/graphene composite (CE-aFeO_x/G) via a facile synthesis route, providing a viable strategy for advancing conversion-type transition metal oxide (TMO) anodes. Owing to its amorphous nature, absence of grain boundaries, loose packing, strong interfacial bonding, and isotropic properties imparted by carbon encapsulation, CE-aFeO_x/G facilitates spatially uniform electrochemical phase transitions during lithiation. This promotes the in situ formation of ultrafine Fe clusters with high electrochemical activity, which is essential for achieving long-term cycling stability. As a result, the composite anode exhibits outstanding electrochemical performance: a reversible capacity of 1134.5 mAh g^–1 at 100 mA g^–1 with nearly 100% retention over 270 cycles and only 4.1% capacity decay after 1130 cycles at 300 mA g^–1. This work not only sheds light on the degradation mechanisms of FeO_x-based anodes but also opens a promising avenue for enhancing the durability of conversion-type Fe-based TMO anodes in high-performance LIBs.

The practical application of metal–organic frameworks (MOFs) in water remediation is often hindered by their powdery nature, which causes aggregation, difficult recovery, and potential secondary pollution. To address this, we pioneer an integrated strategy of chemical bonding and in situ epitaxial growth to fabricate, for the first time, a robust and substrate-anchored cyclodextrin-based MOF (CD-MOF) composite. The innovation centers on using ethylenediamine-modified β-cyclodextrin (EDA-β-CD) as chemically grafted nucleation sites on aldehyde-functionalized polystyrene to guide the oriented growth of CD-MOF, yielding a well-adhered PS-CD-MOF composite. This novel material exhibits excellent adsorption of sulfonamide antibiotics (e.g., 5.55 μg·mg^–1 for sulfadimethoxine) with rapid kinetics. More importantly, it demonstrates outstanding reusability over multiple cycles while maintaining structural integrity, thereby overcoming a key limitation of powder MOFs. Its versatile adsorption across different sulfonamides confirms the success of the synthesis strategy and highlights its potential as a stable, recyclable platform for waste liquid.

Against the backdrop of escalating ecological and energy crises, producing hydrogen peroxide (H₂O₂) from water photocatalytically has attracted significant attention as a sustainable solution. COFs are promising photocatalysts for H₂O₂ synthesis because of their tunable porous structures and high surface areas. However, the practical application of COFs is limited by rapid charge-carrier recombination and poor hydrophilicity. Here, an S-scheme heterojunction was constructed by in situ growing In₂S₃ on a COF substrate. The incorporation of In₂S₃ enhanced the light absorption and hydrophilicity of COF and accelerated the charge separation and transport. The synergy of hydrophilicity and an S-scheme heterojunction in In₂S₃@COF-30 contributed to the improved photocatalytic H₂O₂ production rate (1101.85 μmol g^–1 h^–1) in pure water without sacrificial agents. This work presents a strategy for designing hydrophilic S-scheme heterostructures to overcome the limitations of COF-based photocatalysts and advances sustainable, solar-driven H₂O₂ production.

The development of multifunctional nanoscaffolds offers a promising approach for the simultaneous diagnosis and therapy of various diseases. In this study, we designed and evaluated a multifunctional theranostic nanoscaffold termed FLAB, which consists of four integrated components: nanoparticles of iron oxide (Fe₃O₄) functionalized with polyethylenimine (F), liposomes (L), a targeting aptamer (A), and the fluorescent dye [2-(4-(5,5-difluoro-5H 4λ⁴,5λ⁴-dipyrrolo[1,2-c:2′,1′-f][1,3,2]diazaborinin-10-yl)phenoxy)ethan-1-ol] (BODIPY, B). Upon encapsulation of the chemotherapeutic agent cisplatin (c), the nanoscaffold is referred to as FLABc. This nanomodular design enables both targeted drug delivery and imaging capabilities, making FLAB and FLABc promising candidates for theranostic applications. While cisplatin was selected as a model chemotherapeutic agent for lung cancer treatment, the nanoscaffold can be readily adapted to deliver alternative drugs for other pathological conditions. The targeting aptamer, which can be substituted to recognize different molecular biomarkers, enables disease-specific delivery and enhances therapeutic precision. Physicochemical characterization confirmed successful assembly and stability of the nanoscaffold. Cytotoxicity assays performed on MRC-5 (normal lung fibroblasts) and H1299 (nonsmall cell lung carcinoma) demonstrated that FLABc effectively reduced cancer cell viability while minimizing the cytotoxicity typically associated with free cisplatin. Flow cytometry revealed high apoptosis induction in H1299 lung cancer cells, and fluorescence microscopy confirmed efficient cellular uptake and localization. BODIPY-labeled FLAB nanoscaffolds are partially internalized in vesicles of H1299 cells, indicating trafficking to late endosomes/lysosomes. This distribution may facilitate intracellular cisplatin release and enhance therapeutic activity. These findings support the potential of FLAB as a flexible and targeted theranostic tool, capable of integrating drug delivery and diagnostic capabilities in a single nanosystem for cancer and beyond.

Electrochemical nitrate reduction reaction (NO₃RR) to ammonia (NH₃) represents a sustainable route for both wastewater purification and value-added chemical product. However, developing industrially viable catalysts that combine high efficiency and robust durability remains a challenge. Here, we engineer a series of Mn-doped Co₃O₄ catalysts with controlled Mn contents via a metal–organic framework (MOF)-derived approach. A distinct volcano-type relationship is observed between the Mn doping level and the NO₃RR performance, where optimal Mn₁₅–Co₃O₄ achieves a remarkable nitrate (NO₃^–) conversion of 95.48%, 99.19% selectivity and 96.71% Faradaic efficiency toward NH₃. More importantly, we unveil that this activity trend is synchronously mirrored by the evolution of three key descriptors: the electrochemically active surface area, the Co²⁺/Co³⁺ ratio, and the concentration of oxygen vacancies, all peaking at the same optimal doping level. This correlation establishes a robust structure–activity relationship, demonstrating that moderate Mn doping maximally synergizes morphological advantages and electronic modulation. This work offers an intriguing pathway for the application of MOF-derived materials and provides valuable insights for the rational design of efficient electrocatalysts.

Bismuth chalcogenides have gained widespread interest as conversion-alloying-type anode materials for lithium-ion batteries due to their large interlayer space, multielectron reactions, etc. These merits can endow bismuth chalcogenides with a Li⁺-storage capacity that is higher than that of the commercial graphite anode. Nevertheless, their volume variation upon cycling can destroy the structural integrity, resulting in irreversible capacity damping. Herein, the sheet-like composite (Bi₂Se₃–CDs), with Bi₂Se₃ nanosheets uniformly modified with ultrasmall carbon dots (CDs), was successfully designed via a facile one-step solvothermal process. Ultrasmall CDs (∼3.7 nm) efficiently increase the electrical conductivity and surface-specific area, thereby intensifying the lithium-ion/electron transport kinetics of the Bi₂Se₃ electrode. Additionally, the formation of the covalent bond (C–O–Bi) between Bi₂Se₃ and CDs further accelerates charge transfer and guarantees structural integrity upon cycling. Consequently, the obtained Bi₂Se₃–CDs composite anode delivers comprehensive Li⁺-storage properties, including a relatively high initial Coulombic efficiency (76.2%), high reversible capacity (586 mAh g^–1 at 100 mA g^–1 after 50 cycles), and decent prolonged cycling stability (93.1% capacity retention after 300 cycles at 500 mA g^–1). This study presents an efficient approach to constructing advanced bismuth-chalcogenide-based lithium-ion battery composite anodes.

Artificial photosynthesis provides a sustainable route for the synthesis of high-value chemicals from CO₂, yet its efficiency remains limited by low light utilization and fast charge recombination. Here, a direct Z-scheme BaTiO₃/BiOCl (BTO/BOC) heterojunction was prepared using a hydrothermal synthesis route. Owing to the combined effects of piezoelectric polarization and Z-scheme charge transfer, the heterojunction achieved a CO₂ reduction rate of 56.45 μmol g^–1 h^–1 under simultaneous application of light and ultrasonic irradiation, corresponding to 2.06- and 7.49-fold enhancements compared with pure BiOCl (BOC) nanosheets and BaTiO₃ (BTO) nanoparticles, respectively. This study demonstrates a piezoelectric-assisted photocatalytic strategy, providing valuable insights into efficient CO₂ conversion and sustainable energy development.