ACS Applied Nano Materials最新文献

Diabetes remains a significant chronic disease, with its prevalence projected to exceed 700 million by 2045. Monitoring glucose levels through conventional methods is crucial for mitigating the associated health risks. In this study, NiTiO₃ films are loaded on TiO₂ nanorods to create photoanodes, which are applied for glucose detection using near-infrared (NIR) light illumination. This approach achieved a detection limit of 0.01 mM with selectivity reaching up to 95%. Additionally, the long-term stability was confirmed for at least 16 weeks. This study demonstrates the potential of using NiTiO₃-based nanomaterials as an NIR-driven sensor for glucose detection.

In this work, we report Rh nanoparticles encaged in hollow porous silica nanospheres (Rh@HPSNs) as highly active toluene hydrogenation catalysts under mild reaction conditions. Poly(ethylenimine)/poly(acrylic acid) (PEI/PAA) micelles in a water–ethanol system were used as templates for silica deposition to synthesize core–shell-structured silica-coated PEI/PAA micelles, which were further soaked in a solution of Rh precursors, washed, calcined, and subsequently reduced by H₂ to obtain Rh@HPSNs, featuring small Rh nanoparticles in highly porous hollow silica nanospheres. The synthesized Rh@HPSNs illustrate high catalytic activities for toluene hydrogenation at 0.1 MPa H₂ and 30 °C and achieve a methylcyclohexane yield of >99% at a reaction time of 2.0 h and a toluene/Rh ratio of 500/1. To our best knowledge, Rh@HPSNs are comparable to state-of-the-art Rh-based catalysts at mild conditions for toluene hydrogenation, and the enhancement is ascribed to small-sized Rh particles efficiently utilizing the Rh metal, highly porous hollow silica nanospheres to accelerate mass transfer, and the protections of silica shells to the inner catalytic functionalities.

Gold nanotriangles, one of a family of nanoprisms, have attracted a great deal of interest due to their promising applications in catalysis, electronics, imaging, diagnostics, and photothermal therapy. The crucial role of iodide in the formation of anisotropic gold nanotriangle (AuNT) has been assigned to the inhibition of Au(111) facet growth and as a digestion agent (as I₃^–) of non-nanotriangle impurities. However, neither I^– nor I^3– are detectable in the reaction conditions of the growth solution. Instead, an Au(I) complex, [AuI_yCl_2–y]^-, has been identified for the first time as a synthetic precursor of Au nanotriangles. This complex forms in solution on mixing AuCl₄^–, I^–, and ascorbic acid. [AuI_yCl_2–y] is readily reduced by ascorbic acid to form in situ AuNP seeds. Preferential adsorption of in situ generated I^– on the Au(111) facets of the Au(0)NP seeds, relative to the Au(100) edges of a developing plate, results in the selective growth of the latter compared to the former. Control of the formation and reaction conditions of this precursor complex provides an entry point to the sought-after reproducible, one-pot synthesis of AuNT. This refinement of the role of iodide introduces approaches to control the outcomes of the metal nanoparticle synthesis.

The activation process is a key step in preparing porous carbon. Herein, three kinds of green activators were separately used to successfully prepare N-doped porous carbons through a two-step strategy: hydrothermal carbonization and chemical activation using microcrystalline cellulose as the carbon source and urea as the nitrogen source. Palladium was deposited on these N-doped microcrystalline cellulose-based carbons (NMC-X, where X represents the activator) via a traditional deposition–precipitation method, and the resulting Pd nanoparticle catalysts (Pd/NMC-X) showed high activity in the selective hydrogenation of quinoline under mild conditions, particularly Pd/NMC-ZC (ZC, zinc carbonate), which achieved complete conversion of quinoline within 100 min at 40 °C and 4 atm H₂. Characterization results suggest that the high activity of Pd/NMC-ZC is mainly attributed to the special electronic structure of its Pd species, particularly the distribution of valence states and reducibility of Pd and the high hydrogen spillover capacity between Pd and NMC-ZC. The chemical activation by ZC leads to the formation of multiple defect sites on the carbon skeleton, modifying the carbon surface properties to enhance hydrogen spillover. This also provides an excellent environment for Pd nanoparticle anchoring, thus increasing the Pd-support interactions and regulating the electronic structure of Pd.

Liquid crystal films play a key role in advancing next-generation optical and photonic devices that require a precise in-plane modulation of optical anisotropy. This study employs multiphoton direct laser writing, a high-resolution three-dimensional (3D) printing method, to fabricate pseudoperiodic patterns of lines and grooves on glass surfaces for the in-plane alignment of liquid crystal films. Single layers of lines with submicron thickness and line spacing were fabricated in less than half an hour and forced the in-plane alignment of a liquid crystal film with a thickness of about 10 μm. We validate the method on patterns with singular topologies designed to induce the nucleation of disclination defects with a predetermined spatial arrangement, orientation, and topological strength. Compared to other surface patterning methods, high-resolution 3D printing provides the unique advantage of direct surface fabrication, enabling the creation of nonflat geometries such as terraces and lenses and expanding the design and functionalities of liquid crystal devices. We anticipate that this method will be used to create thin-film devices such as polarization gratings, beam steerers, and q-plates for manipulating polarized and structured light.

Achieving high catalytic activity and stability with low platinum loading is vital for reducing the cost of proton exchange membrane fuel cells (PEMFCs) and enabling their large-scale commercialization. Herein, a three-dimensional (3D) nitrogen sulfur codoped carbon nanocomposite support embedded with Co nanoparticles derived from sulfur-doped zeolite imidazolate frameworks-67 was synthesized. After Pt nanoparticles are loaded, it can act as an excellent ORR catalyst (3D LPCNSC) for hydrogen–oxygen fuel cells. The existing metal Co are beneficial for catalyzing the growth of carbon nanotubes, generating CoN_x structures, and partially forming Pt–Co nanoalloys. Nitrogen sulfur codoping can enhance metal–support interactions between Pt/Pt–Co and sulfur-doped Co–N–C by regulating the interfacial charge transfer. The 3D conductive network constructed using graphene oxide and carbon nanotubes contributes to enhanced electron and mass transfer. As a result, the 3D LPCNSC catalyst with a relatively lower Pt loading (13.65%) exhibits a superior half-potential, higher mass activity, and superb stability in comparison to commercial Pt/C (20%). A membrane electrode assembly assembled with this catalyst achieves a peak power density of 983.8 mW cm^–2 in a hydrogen–oxygen single cell. This work highlights a promising avenue for the structure and component design of low platinum nanocatalyst for PEMFCs.

Oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) are two important reactions in clean energy conversion devices. It is necessary to develop nonprecious metal-based bifunctional catalysts for ORR and OER. In this work, a multimetal bifunctional catalyst, nanoparticles of trimetallic CoFeZn supported on N-doped carbon (CoFeZn/NC), is prepared by one-step carbonizing the mixture of M-ZIFs (M = Fe, Co, and Zn), carbon black, and melamine. CoFeZn/NC has a more mesoporous structure and a higher specific surface area of 1029.6 m²/g compared to FeCo/NC, which is attributed to the easy volatilization of Zn at high temperatures. It also has high contents of pyridinic N (35.8%) and pyrrolic N (31.1%), abundant metal active sites, and exhibits strong synergistic effects between these nanoparticles of metals. Better than the single-metal catalysts (Co/NC, Fe/NC, and Zn/NC) and bimetallic catalysts (CoFe/NC, FeZn/NC, and CoZn/NC), CoFeZn/NC has an ORR peak potential of 0.90 V (vs. RHE) and a half-wave potential of 0.87 V (vs. RHE) in 0.1 M KOH solution, and exhibits excellent stability and methanol resistance. For OER, CoFeZn/NC has the lowest overpotential of 319.9 mV at a current density of 10 mA/cm² and a Tafel slope of 82.47 mV dec^–1.

Neoadjuvant immunotherapy is superior to adjuvant immunotherapy in terms of immune suppression relief and antitumor immunity activation but inevitably suffers from immune-related toxicities. To minimize the toxic side effects, a local metronomic mild-temperature photothermal therapy (PTT) is proposed herein as a neoadjuvant immunotherapy. It was disclosed that the Prussian blue nanoparticle (PBNP)-mediated metronomic mild-temperature PTT effectively inhibited the growth of both primary and distal tumors on 4T1 xenograft tumor-bearing mice by effectively reversing the immunoimpressive TME through repolarizing M2-like TAMs to tumoricidal M1-like ones. Synergistically, the reprogrammed M1-like phenotype upregulated the percentage of cytotoxic T lymphocytes in the spleen and tumor, leading to an activated systemic immunity. This together with the demonstrated biosafety underscores the great potential of PBNP-mediated metronomic mild-temperature PTT as immunotherapy for reducing tumor burden presurgery and preventing tumor reoccurrence and metastasis postsurgery with minimized side toxic effects.

Single-atom catalysts have the advantage of high chemical efficiency, which requires atomic-scale control during catalyst formation. In order to address this challenge, this work explores the synthesis of single-atom platinum (SA-Pt) catalysts using atomic-layer deposition (ALD) on vertical graphene (VG), in which a large number of graphene edges serve as energetically favorable nucleation sites for SA-Pt, as predicted by density functional theory calculations. Interestingly, SA-Pt has been achieved on VGs at low ALD cycle numbers of up to 60. With a further increase in the number of ALD cycles, an increasing number of Pt clusters with diameters <2 nm and Pt nanoparticles (NPs) with diameters >2 nm become dominant (nano-Pt @VG). This is in contrast to the observation of predominantly nano-Pt on other carbon nanostructures, such as carbon nanotubes and monolayer graphene, under the same ALD growth conditions, indicating that the edge states on VG indeed play a critical role in facilitating the formation of SA-Pt. Profound differences are revealed in a comparative study on H₂ sensing. SA-Pt exhibits both a higher sensitivity and faster response than its nano-Pt counterpart by more than an order of magnitude, illustrating the high catalytic efficiency of SA-Pt and its potential for gas sensing and a variety of other catalytic applications.

Oral delivery of insulin exhibits low bioavailability due to the hydrolysis in acidic gastric juice, biodegradation of enzymes, and inefficient penetration through the intestinal mucus and epithelial cell layer. Here, we report a micelle platform to enhance the oral delivery of insulin. Insulin was precipitated by zinc ions to form hydrophobic nanoparticles and subsequently coated with a surfactant polysorbate-80 (Tween-80) to form nanosized micelles (TW-Zn-rhINS). Tween-80 protects the insulin from the degradation of enzymes, meanwhile facilitating the diffusion within mucus and the epithelial cell layer by opening the tight junctions. The micelles were then lyophilized and encapsulated in enteric capsules to overcome acidic hydrolysis in gastric juice. The micelles significantly increased transcellular insulin transport and uptake. The in vivo experiments demonstrated that oral TW-Zn-rhINS micelle capsules (30 IU/kg) decreased the blood glucose of diabetic mice by 58.74% after administration for 6 h, while the postprandial blood glucose dropped by 51.1%. Pharmacokinetics data indicated that the relative oral bioavailability of TW-Zn-rhINS was 7.88%, which was 7.73 times higher than that of insulin. The micelles present a promising platform to enhance the oral bioavailability of insulin, also indicating a potential for oral delivery of protein.