ACS Applied Nano Materials最新文献

In this study, we investigated the degradation behavior of CeO₂-based nanoparticles as oxygen carriers for the chemical looping process. In the investigation of the dependency of the reaction gases on the degradation in terms of changes in the CeO₂ crystallite, H₂O and H₂ caused the most significant increase in the crystallite size (sintering) compared with other gases. It was found that Pt decoration, a well-known method for the enhancement of performance as an oxygen carrier, was effective in suppressing the sintering in various reaction gases. On the other hand, mixing with ZrO₂ nanoparticles that are not reactive as oxygen carriers also improves the durability of CeO₂. The sintering-prevention effect of mixing ZrO₂ nanoparticles as nano-obstacles also contributes to exploiting the intrinsic catalytic activity of CeO₂ nanoparticles. Mixing with other nanomaterials would be a universal strategy for improving the durability and activity of thermodynamically unstable nanocatalysts.

Supraparticles, particles composed of individual nanoparticles, have attractive properties, but their applicability in real-world applications is often restricted by their comparably small dimensions. Suprabeads, in which individual supraparticles are fixed to a larger support bead with the help of a binder, have been proposed to address this challenge. These suprabeads retain the the unique functionalities of both the nanoparticles and supraparticles while offering millimeter-sized dimensions for facilitated handling. Here, we investigate the role of the binder in the formation and functionalization of suprabeads. First, we focus on the thermal, mechanical, and chemical stabilities of suprabeads as a function of their binder composition. Our results show that binders containing organic groups offer room-temperature curability, while the chemical and thermal stability of the resulting suprabeads is limited and their mechanical stability depends on the flexibility of the binder. Inorganic binders drastically increase the temperature stability but are inherently more brittle. Second, we demonstrate that wetting the supraparticle with the binder layer enables us to tailor the resultant suprabead functionality. While a low degree of embedding provides accessible supraparticles, a larger degree of embedding induces tunable protection of the supraparticles from the environment. To highlight the versatility of the suprabead concept, we demonstrate that the ideal binder material can be identified for a specific application, such as ammonia indication or propane dehydrogenation.

In this study, mesoporous carbon microspheres (MCMs) with a large specific surface area (865 m²/g) and excellent pore structure were synthesized using sucrose as a carbon source and hollow mesoporous silica spheres as a template. Subsequently, highly dispersed tin dioxide nanoparticles were loaded on MCMs by an impregnation method, yielding bifunctional catalysts (xSnO₂/MCMs) with both Brønsted and Lewis acidic sites. The ratio of Lewis acid to Brønsted acid and the overall acid density on the xSnO₂/MCMs were controlled by adjusting the amount of SnO₂ loading. Under optimal conditions (170 °C, 5 h), the 20%SnO₂/MCMs exhibited excellent catalytic performance, thereby achieving a 94.9% glucose conversion and a 75.7% HMF yield in an aqNaCl-H₂O/THF biphasic solvent system. Additionally, the 20%SnO₂/MCMs exhibited exceptional stability with constant HMF yields at 65% during five consecutive cycles and a little drop in glucose conversion. This research offered a viable approach for effectively converting glucose to HMF.

The reduced graphene oxide/ultrathin nanotube Bi₅O₇I (rGO/UN-Bi₅O₇I) was well synthesized via a simple method to investigate the charge transfer and light-harvesting ability and its efficient application in wastewater problems such as organic (Methylene blue) and inorganic (Cr⁶⁺) pollution. The analysis shows the synergistic effect of the graphitic structure of rGO and the ultrathin nanotube structure of Bi₅O₇I, leading to efficient light harvesting and charge transfer. The efficient photocatalytic activity of this photocatalyst was achieved with 20% rGO. The optimum pH, ionic strength, and time for the photodegradation of MB were 12.0, 0.05 M, and 4 min, and those for the photoreduction of Cr⁶⁺ were 2.0, 0.10 M, and 38 min, respectively. In addition, the experimental data for MB investigation show that the kinetic surface adsorption model follows the Langmuir isotherm [Q_max = 350.00 (mg/g)] model. The kinetic isotherm of the surface adsorption is observed by pseudo-first-order kinetics [Q_e.cal = 136.87 (mg/g)]. Also, the photodegradation efficiency of UN-Bi₅O₇I and rGO/UN-Bi₅O₇I was compared, and the results showed that the kinetic rate constant of rGO/UN-Bi₅O₇I for the photodegradation of MB was 14 times, and that for the photoreduction of Cr⁶⁺ was 4.5 times higher than UN-Bi₅O₇I. The scavenger test showed that the hole (h⁺) and superoxide radical (^•O₂^–) have the main role in the photodegradation of MB. The rGO, due to its functional groups, improved the surface adsorption of pollutants and caused the photodegradation of MB by h⁺ and the photoreduction of Cr⁶⁺ to Cr³⁺ by electrons. Consequently, rGO/UN-Bi₅O₇I can be efficiently utilized in environmental pollutant remediation.

Magnesium hydride (MgH₂) is widely recognized as a prominent solid-state hydrogen storage material, notable for its high hydrogen storage capacity and lightweight characteristics. However, its application is hindered by a high dehydrogenation temperature and slow kinetics. Ceria serves as a highly effective catalyst for enhancing the kinetic performance of MgH₂, primarily due to its rich concentration of oxygen vacancies. In this work, cerium dioxide (CeO₂) crystals with different morphology are prepared (nanoparticles and nanorods), which exposed different crystal facets (100) and (111), respectively. The results indicate that the (100) crystal plane exhibits a greater affinity for hydrogen atom adsorption, leading to the formation of CeH_2.73. This interaction facilitates both the dissociation of hydrogen molecules and the diffusion of hydrogen atoms, thereby enhancing the hydrogen absorption properties of MgH₂. The (111) crystal plane contains more oxygen vacancies, attracting negatively charged H^–, dissociating the Mg–H bonds, and thus improving the hydrogen desorption properties of MgH₂. In this study, we propose a strategy to optimize the morphology and crystallographic features of the catalyst to enhance its catalytic activity and thus improve the hydrogen storage performance of MgH₂.

Antimony (Sb) exhibits excellent conductivity and reactivity with sodium ions, which can be attributed to its distinctive puckered layer structure. Additionally, it has the potential to achieve a high theoretical capacity of 660 mAh g^–1 through the formation of Na₃Sb. However, the significant volume expansion (approximately 390%) that occurs during the charging process restricts its practical applications. To tackle these challenges, we developed a fast Joule heating technique to successfully ultrafast construct Sb nanoparticles into the bead-like structure of N,S-codoped asphalt-based carbon fibers (N/S-CNF). This unique bead-like structure effectively inhibits the volume expansion of the metal during the charging and discharging process. In addition, the 1D carbon nanofibers contribute to the formation of a robust electrode framework and enable fast electron transfer during cycling to facilitate the kinetics. These advantages together contribute to the excellent cycling stability and rate performance of self-supported Sb@N/S-CNF nanocomposites used as anode materials for sodium-ion batteries (SIBs). The specific capacity was still as high as 263.46 mAh g^–1 at 0.1 A g^–1after 150 cycles and 221.1 mAh g^–1 at 0.5 A g^–1 after 750 cycles with a capacity retention rate of 83.9%. These findings provide ideas for the ultrafast preparation of binder-free Na⁺ storage nanomaterials.

Neuroblastoma is a prevalent extracranial solid tumor that mainly affects children, for which current therapies often cause significant side effects due to limited specificity. To address this, nanomedicine has introduced engineered nanocarriers for targeted drug delivery, yet challenges such as poor tumor perfusion and immune clearance remain. Herein, we present an approach using bifunctional nanosized liposomes to enhance immune cell targeting of neuroblastoma cells through click chemistry. These liposomes, functionalized with azide or strained alkyne groups and targeting moieties, were designed to selectively label macrophages and neuroblastoma cells, facilitating their recognition through bio-orthogonal chemical reactions. In vitro studies under physiological flow conditions demonstrated the successful labeling of both cell types and subsequent interaction, mimicking the in vivo environment. This strategy could change the current paradigm of cell-based treatments for solid tumors like neuroblastoma, owing to an improvement in the immune cell targeting efficacy.

Rechargeable aqueous zinc-ion batteries (AZIBs) have attracted increasing attention owing to their high theoretic capacity and safe nonflammable electrolytes. Vanadium-based cathode materials have emerged as promising candidates for AZIBs owing to their multivalent redox chemistry and expanded interlayer architectures for high specific capacity. In this work, (NH₄)_1.32Na_0.95V₆O₁₆·1.88H₂O (NNVO) is developed as a high performance cathode material for AZIBs. In this work, Na⁺ not only serves as a pillar to increase the interlayer spacing but also acts as a guest sacrificial template for intercalated Zn²⁺ ions. The residue Na⁺ still works as a pillar to support the vanadium layers, and the replaced Na⁺ by Zn²⁺ works as a guest sacrificial template to make it easier for the host accommodating Zn²⁺, thereby stabilizing the interlayer spacing. As a result, The NNVO cathode exhibits a good rate capability, achieving a capacity of 460.2 mAh g^–1 at 0.1 A g^–1 and 195 mAh g^–1 at 5 A g^–1, a good stability with 89.6% retention after 3500 cycles at 5 A g^–1. This work provides a reference for engineering cathode materials in aqueous batteries.

Here, we have reported the fabrication of a wearable, flexible piezoelectric nanogenerator (PENG) based on PVDF nanocomposites where graphene nanoplatelets (GNPs) inserted into metal–organic framework (MOF)-derived ZrO₂ (ZrO₂-GNP) are used as a piezoelectric filler for β-phase stabilization of the PVDF polymer. The MOF route is suitable in improving the surface area of the ZrO₂ resulting in better chemical interaction between the polymer matrix and the filler. In addition, the GNP improves the conductivity of the nanocomposites along with the device performance. The as-fabricated device with the highest loading of 5 wt % ZrO₂-GNP in PVDF shows the highest open-circuit voltage of ∼60 V and short-circuit current of ∼2.2 μA under human finger imparting (F ∼15.5 N). Also, under a piezo-tribo-imparting machine (F ∼2.31 N), it shows an output voltage of ∼35 V. The highest power density obtained from the PENG is ∼40 μW/cm², which is the adequate amount for powering up portable electronic devices like LEDs, calculators, wristwatches, etc. This PENG is also suitable for various kinds of applications, as it can generate voltage from various kinds of mechanical biomechanical forces.

Designing and fabricating photocatalysts with abundant intrinsic active sites and a fast carrier separation capability remains a great challenge for efficient photocatalytic hydrogen evolution reactions (PHERs). In this paper, cobalt (Co) cations are incorporated into two-dimensional (2D) porous ZnIn₂S₄ nanoflakes by a controllable cation-exchange-mediated strategy, and self-adapting S vacancies (Vs) are rationally constructed to stimulate catalytic activity on the inert basal plane. The surface state of ZnIn₂S₄ nanoflakes is regulated by the Vs structure and doped Co atoms through a surface modification strategy to achieve an efficient PHER. Theoretical calculations and experimental results show that by introducing Co dopants into ZnIn₂S₄, Co preferentially replaces Zn atoms and induces the generation of abundant Vs, thus optimizing the adsorption energy of the reaction intermediate (H*) and enhancing the PHER dynamics. The Co dopants and Vs show dominant synergistic effects in modulating the regional charge separation and activating the inert basal plane. More importantly, the optimal PHER rate of Co-ZnIn₂S₄ reaches 1.20 mmol g^–1 h^–1, which is 5.2 times higher than that of the pristine ZnIn₂S₄ nanoflakes. In addition, this robust 2D porous configuration guarantees the stability of the catalytic reaction. The present work gives an expandable direction for enhancing the photocatalytic activity of the basal plane on transition metal sulfides.