ACS Applied Materials & Interfaces最新文献

Cu-modified CeO₂(100) (Cu/CeO₂(100)) has been widely studied for NH₃-selective catalytic oxidation (NH₃-SCO), although most previous theoretical studies considered predefined Cu single atoms, Cu clusters, or CuO_x species, leaving the oxygen-induced reconstruction of the active Cu/CeO₂ surface and its catalytic effect unclear. Here, we employ density functional theory calculations with on-site Coulomb interaction corrections (DFT + U) to identify the stable reconstructed Cu/CeO₂(100) under O₂-rich conditions and elucidate the complete NH₃ oxidation pathways. The calculations reveal that the unique “pocket-like” reconstructed CeO₂(100) surface can drive the aggregation of the isolated Cu atoms into a stable Cu₃O₂ cluster within the pocket area. This restructuring generates active motifs comprising geometrically flexible CuO₄ units and adjacent Ce³⁺ sites, and each CuO₄ unit can facilitate the heterolytic NH₃ dissociation to NH₂*, while the Ce³⁺ site can activate O₂ into superoxide (⁠$O_2^{–}$⁠) species. The activated $O_2^{–}$ species then reacts with NH₂* to form stable NH₂O* and O* intermediates. Moreover, a cooperative dynamic restructuring between NH₂O* and nearby O* species gives rise to a distinctive Ce─O─NH_x···O five-membered ring. This unique configuration enables a nearly barrierless (0.02 eV) proton transfer to produce NHO* and OH* species, ultimately driving the deep oxidation to form NO* and H₂O*. These findings reveal a previously unrecognized pocket-confinement effect on Cu aggregation and redox-site cooperation on Cu/CeO₂(100), providing mechanistic guidance for the rational design of Cu/CeO₂-based NH₃-SCO catalysts under oxygen-rich conditions.

Photobiomodulation using red and near-infrared light has emerged as a promising strategy for promoting skin regeneration because of its ability to stimulate mitochondrial activity and enhance cellular proliferation. However, the optical characteristics of the light source, including angular emission and spectral bandwidth, remain underexplored in terms of their influence on biological outcomes. Here, we demonstrate that emission-engineered red organic light-emitting diodes (OLEDs) can directly regulate cellular responses by tailoring both angular distribution and spectral properties. Flexible OLED devices were fabricated with three representative configurations: an indium tin oxide (ITO)-based Lambertian emission device (inflexible), a candle-emission device with a narrow spectral profile centered at 610 nm, and a batwing-emission device exhibiting angularly broadened and spectrally enriched output (610–650 nm). Systematic optical characterization revealed distinct differences in efficiency, full width at half maximum (FWHM), and angular emission patterns across these devices. Subsequent in vitro assays showed that both candle and batwing devices enhanced proliferation-related cellular responses relative to sham-irradiation and ITO controls, with the batwing device producing the strongest effect. The superior biological efficacy of the batwing device is attributed to its broadened multiwavelength emission, providing broader spectral overlap with biologically relevant wavelengths. The implications of these optical characteristics for tissue photobiomodulation are discussed based on previous studies. This work establishes a direct connection between OLED emission characteristics and biological efficacy, underscoring emission control as a key parameter in optimizing photobiomodulation.

It is remarkably attractive but challenging to develop fine Pt–rare-earth intermetallic catalysts toward efficient and stable oxygen reduction reaction (ORR) for fuel cell applications. In this work, an amino-assisted method was employed to prepare the carbon-supported Pt₅Sm (Pt₅Sm/C) catalyst, which exhibited an average size of 3.8 ± 1.0 nm with a core–shell structure consisting of a Pt-enriched surface over a hexagonal Pt₅Sm intermetallic core. The introduction of Sm into the Pt lattice induced strong electron interactions between Sm and Pt and enhanced the resistance to Pt oxidation, thereby improving the catalytic kinetics and durability for the ORR. In rotating disk electrode tests, the Pt₅Sm/C catalyst delivers a promising ORR activity of 430.3 A·g_Pt^–1 with only a 10.3% loss after 30,000 cycles, significantly outperforming commercial Pt/C. Furthermore, in H₂/air fuel cell tests, the Pt₅Sm/C catalyst exhibited a peak power density of 853 mW·cm^–2 with only a voltage drop of 56 mV at 0.8 A·cm^–2 after 30,000 cycles. This work demonstrates that Pt–rare-earth intermetallic catalysts are promising candidates for high-performance and durable fuel cell applications.

Creating direct pathways that transform dissolved metal waste into functional architecture is central to sustainable nanomanufacturing and circular materials design. Here, we report a redox-driven strategy for the direct conversion of gold (Au) ions from electronic waste into spatially organized Au/MXene nanoarchitectures and electrocatalytic membranes. Ti₃C₂T_x MXene nanosheets exhibit an Au uptake capacity of 3720 mg g^–1 at 1 ppm, together with high selectivity in the presence of excess competing metal ions. Mechanistic studies reveal that the Au capture is coupled with spontaneous interfacial redox conversion, where ∼91% of Au(III) ions are reduced in situ into metallic Au nanoparticles on the MXene surface. Importantly, performing the recovery process in a dispersed colloidal state enables recovery-induced interlayer assembly, producing homogeneous Au distributions throughout the MXene framework after vacuum-assisted membrane formation. In contrast to surface-confined deposition in conventional filtration architectures, the interlayer nanoarchitecture preserves ion-transport pathways and maximizes catalytic accessibility. We further show that ultratrace Au concentrations promote the formation of highly dispersed confined Au domains, enabling efficient electrocatalytic membranes despite substantially lower gold loading. The resulting membranes function directly as flexible binder-free electrodes without additional refining, metal stripping, or catalyst deposition steps. This work establishes a recovery-as-fabrication strategy in which dissolved metal ions are directly transformed into functional nanoarchitectures through coupled redox reduction, confined nucleation, and interlayer assembly.

Achieving stable integration of drug-releasing polymer coatings with load-bearing meniscus implants remains a challenge in biomaterials engineering. In this study, four surface modification strategies, femtosecond-pulsed laser treatment, oxygen plasma, polydopamine, and an ethyl-2-cyanoacrylate (ECA) interlayer, were evaluated for the integration of a dexamethasone (DEX)- and celecoxib (CLX)-releasing bilayer coating with a polycarbonate urethane (PCU) meniscus implant. The selected construct comprised an ECA interlayer applied from a 40% (w/v) solution, a CLX-loaded PLLA/PCL layer prepared at 100 mg/mL and a 53/47 (w/w) polymer ratio with 16.6% CLX loading, and an outer DEX-loaded PLGA layer prepared at 200 mg/mL with 2.44% DEX loading. At 37 °C, compared with uncoated PCU, ECA-containing constructs showed significantly higher storage modulus, loss modulus, and elastic modulus (p < 0.05), while tan δ remained unchanged, indicating preservation of the elastic-dominant viscoelastic response of the complete construct. The ECA-containing coating was subsequently adapted to the geometry of a sheep meniscus implant using an optimized dip-coating procedure. During a 21-day bioreactor study, repeated compression and shear increased cumulative DEX release from 59 to 67% and CLX release from 25 to 40% relative to static controls, while no visible coating delamination was observed. Ethylene oxide sterilization preserved drug loading and release behavior. In an exploratory three-month sheep study, the fiber-fixed coated implants remained in position, and the coating remained macroscopically associated with the retrieved prostheses. These findings support the use of an ECA interlayer to integrate a bilayer drug-releasing coating with a PCU meniscus implant while preserving construct-level mechanical behavior and drug release under the conditions evaluated.

This study proposes a defect engineering strategy that combines low-fluence proton irradiation for leakage current (J_r) suppression and subsequent low-temperature supercritical fluid (SCF) treatment for forward conduction characteristic restoration in β-Ga₂O₃ Schottky barrier diodes (SBDs) with and without NiO guard rings. Mechanistically, the results reveal that proton irradiation and subsequent SCF treatment are not the inverse of each other, as the former primarily introduces gallium vacancies (V_Ga), whereas the latter mainly passivates oxygen vacancies (V_O). On the one hand, for proton irradiation, the introduction of V_Ga reduces the net carrier concentration (N_D – N_A), leading to a significant decrease in J_r, accompanied by an increase in specific on-resistance (R_on,sp). On the other hand, for subsequent SCF treatment, the passivation of V_O effectively enhances electron mobility rather than substantially restoring N_D – N_A, thereby maintaining J_r at the irradiated level and considerably reducing R_on,sp. Consequently, through the above defect modulation in bulk β-Ga₂O₃, SBDs simultaneously achieve a decrease in J_r from 1.16 × 10^–5 to 2.01 × 10^–8 A·cm^–2 at –200 V, a moderate increase in R_on,sp relative to their unirradiated counterparts, and a higher on/off current ratio from 2.28 × 10⁷ to 5.69 × 10⁹ at –200 V. Furthermore, this strategy substantially diminishes the effectiveness of the NiO guard ring in reducing J_r. These findings highlight the potential of this defect engineering as an effective strategy for fabricating high-performance β-Ga₂O₃ SBDs.

Selective oxidation of alkene to valuable chemical feedstocks is challenging due to the seesaw effect between conversion and selectivity. Here, multivariate zeolitic imidazolate frameworks (ZIFs) are transformed into bimetallic oxides with varied morphologies via tannic acid (TA) etching and calcination. Impressively, TA etching results in the formation of oxygen vacancies and pore expansion, and the hollow architecture is generated after pyrolysis, favoring the exposure of more active sites and rapid mass diffusion, as well as inducing prominent void-confinement effects. Besides, the incorporation of nickel ions can introduce an additional type of Lewis acid sites into the resulting bimetallic oxides. The obtained Co₃Ni₁-TA_1.4-10-400 exhibits an effective styrene-to-benzaldehyde oxidation with nearly total conversion and a 99% yield (5 h, 90 °C), approximately 1.9 and 8.3 times higher than those of Co₃Ni₁-TA_1.4-10 (51%) and Co₃Ni₁-O (12%), respectively. Mechanistic investigations for the conversion of styrene to benzaldehyde further indicate that the reaction possibly proceeds via a synergistic mechanism involving both a metal-peroxide pathway and a free-radical pathway. Furthermore, in the presence of sodium bicarbonate, Co₃Ni₁-TA_1.4-10-400 can prove effective in catalytic epoxidation of styrene. This study provides a valid approach for the construction of ZIF derivatives with abundant oxygen vacancies and unsaturated metal sites as promising catalysts for fine and commodity chemical production.