ACS Applied Nano Materials最新文献

Nanoscale semiconductor materials are highly effective catalysts due to their high surface-to-volume ratio, enhanced charge carrier separation, and increased active site density. Integrating them into three-dimensional porous supports optimizes mass transport, facilitating efficient adsorption of volatile organic compounds (VOCs) and catalytic interactions. A flexible hybrid photocatalyst was designed by immobilizing zinc oxide (ZnO) nanorods (NR) on the three-dimensional polyurethane (PU) foam support. The polymer surface was functionalized by chemical solution treatment to increase the adhesion between the catalyst and the surface. ZnO NRs were grown on all strut surfaces of the PU foam via a seed-mediated approach. Photocatalytic experiments were carried out in a laboratory-scale plug flow type photoreactor under UVA light irradiation. The effects of parameters such as initial concentration (ppm), relative humidity (RH) (from 0% to 65%), air flow rate (0.3, 0.6, and 1 L/min), and temperature (from 21 to 35 °C) on the gas phase toluene, ethylbenzene, and chlorobenzene removal were evaluated. In the presence of RH, photoreactions accelerated, leading to an increase in the CO₂ conversion rate. The optimum RH value was determined as 30% according to the maximum removal rate. Similarly, removal efficiencies were improved at temperatures higher than room temperature, and the optimum temperature was evaluated as 30 °C. However, as the initial concentration and air flow rate increased, the degradation rates decreased. Maximum VOC degradation rates of toluene, ethylbenzene, and chlorobenzene were obtained as 81%, 71%, and 92% by simultaneous adsorption and photocatalytic oxidation under UVA light at 30% RH and 30 °C, respectively. Chlorobenzene showed a higher removal efficiency than toluene and ethylbenzene for all conditions. The hydrophilic nature of the ZnO NR surface promoted the adsorption of chlorinated compounds. The interaction of VOCs with the catalyst surface revealed that surface chemistry plays a significant role in photocatalytic removal.

With the accelerated development of industrial and agricultural activities, phosphorus pollution has emerged as a global environmental issue. The adsorption method has been widely applied to treat phosphorus contamination. The development of a cost-effective adsorbent for phosphate removal is crucial for the adsorption process. In this study, dumbbell-shaped nanoporous CaCO₃ (DNPCC) featuring a mesoporous nanorod-assembled structure was synthesized via a simple precipitation-calcination method as the adsorbent for phosphorus-containing wastewater. Hierarchical calcium oxalate monohydrate (COM) was first prepared using ethylene glycol (EG) and sodium alginate (SA) as morphology-directing agents, then DNPCC was obtained through calcination of COM. The influence of EG and SA on DNPCC was systematically investigated. DNPCC exhibited remarkable phosphate removal performance in simulated phosphorus wastewater and landfill leachate, respectively, which was attributed to the synergistic effects of high Brunauer–Emmett–Teller (BET) surface area, mesoporous architecture, and positive surface charge. Kinetic studies revealed that the adsorption process was predominantly governed by chemical adsorption. It had a theoretical maximum adsorption capacity of 94.3 mg/g, surpassing that of most reported adsorbents. Thermodynamic analysis further demonstrated that the adsorption process was spontaneous, endothermic, and characterized by increased randomness. Additionally, DNPCC effectively overcomes the interference of various competing ions and maintains a high phosphate removal rate of 83.15%, even after five adsorption cycles. The electrostatic attraction and ligand exchange were the dominant adsorption mechanisms of phosphorus using DNPCC. This study highlighted DNPCC as a highly efficient and selective adsorbent for phosphate removal, offering promising potential for addressing water pollution challenges.

The emerging field of valleytronics has sparked significant interest in controlling valley pseudospin in monolayer transition metal dichalcogenides (ML-TMDs). However, maintaining valley polarization (VP) is challenging at high temperatures and during off-resonance excitation. In this study, we introduce an electrostatically tunable single-contact device based on ML-WSe₂, which demonstrates enhanced photoluminescence intensity and VP modulation under off-resonance conditions compared to conventional back-gate methods. Our findings could be illustrated by an electrostatic doping model, which suggests stronger and more uniform doping at the device center. Furthermore, a clear controllability of trion VP switching is also demonstrated over a wide temperature range. The efficient VP control in ML-TMD via the single-contact design enables future applications in valleytronics and optoelectronics.

The use of two-dimensional materials in the semiconductor industry is growing rapidly, showing promise for dramatically improving device performance. Among the wide range of 2D materials, BN is in the spotlight due to its potential use as an ideal substrate in graphene electronic devices or as intermetal and interlayer dielectric barrier with low-κ. Conventional approaches rely on BN transfer from the growth substrate, typically polycrystalline metals, to the corresponding substrate for characterization or device fabrication, a process not exempt from structural risks or contamination, because it implies the use of postprocessing techniques to obtain samples with the desired characteristics. Therefore, direct growth of BN on semiconductor or dielectric substrates is a necessity for the optimal performance of BN to become a reality. In this work, we use density-functional theory (DFT) and ab initio molecular dynamics (AIMD) to model chemical vapor deposition (CVD) and plasma enhanced CVD (PE-CVD) of a BN monolayer on silicon surfaces. In our simulations, single and multiple compound molecular precursors were modeled, selecting borazine (B₃H₆N₃) and diborane/ammonia (B₂H₆/NH₃) as model systems. Precursor decomposition during plasma-assisted processes determines to a large extent the growing modes of BN, but overall mechanisms for BN growth on semiconductor surfaces are complex and diverse, involving not only surface chemical reactions and kinetic effects but also dynamical effects such as strain-driven precursor dissociation or dissociative chemisorption pathways on surface sites next to a previously deposited molecular precursor. Our simulation results accurately describe not only the initial decomposition reactions and growth stages but also the electronic, thermodynamic, and vibrational signatures of the formed BN monolayer. Then, precursor-dependent bonding characteristics allow for the identification of experimentally measurable relevant properties such as infrared (IR) spectra or κ values, which will help optimize precursor usage and interpret the sometimes obscure experimental information, identifying specific measurements to the corresponding submonolayer BN bonding moieties.

Transition metal selenides have attracted much attention as electrode materials for supercapacitors, and reasonable morphology control strategies can effectively improve their actual energy storage capacity and performance. Here, we synthesized (Ni,Co)Se₂ nanosheet arrays with a nanopetal and nanoagaric morphology on a flexible carbon cloth by simply adjusting the solvothermal reaction conditions. It was found that compared with the nanoagaric (Ni,Co)Se₂ nanosheet array, the nanopetal (Ni,Co)Se₂ nanosheet array has a more highly ordered structure and larger specific surface area, which can provide a large number of reaction sites and promote the transfer of electrons and ions, which effectively enhances the performance of the supercapacitor. The power density of asymmetric supercapacitors with the nanopetal (Ni,Co)Se₂@CC as the positive electrode is 250.0 W kg^–1, while the maximum energy density can reach 75.3 Wh kg^–1, demonstrating superior performance compared to other similar materials. This work provides a new method for the design of electrode material morphology for high performance.

Isolated single-atom catalysts (SACs) are famous for their exceptional catalytic characteristics. Developing single-atom catalysts provides a maximum atom utilization efficiency. Moreover, it lowers the overpotential and effectively catalyzes the charge and discharge processes to attain the high specific capacity and high-rate cycling performance of lithium-rich oxygen batteries. Single atoms, despite their potential, are inherently unstable due to their high surface energy, which drives them to aggregate during synthesis and catalytic reactions. This aggregation poses a significant challenge in the creation of isolated single-atom catalysts with long-term stability. In this work, we present a novel, gentle synthesis approach to fabricate a stable iridium single-atom electrocatalyst (Ir/N-PAQR SAC). To keep the structural stability and catalytic activity of a single-atom catalyst, the SAC approach is preferred over high-energy ball milling for the synthesis of cathode material (Li₂O/Ir/N-PAQR SAC). A low-metal-loading (2.73%) iridium single-atom electrocatalyst effectively catalyzed the conversion reaction in the cathode during charging and discharging, lowered the charge polarization, and achieved a high discharge capacity of 455 mA h g^–1, at 0.1C, and a high rate capacity of 434 mA h g^–1 at 1C. It also exhibits an outstanding cycling performance at 1C with a capacity retention of 86.8% after 100 cycles. Furthermore, the Li₂O/Ir/N-PAQR SAC cathode shows fast charging with the capacity of 120 mA h g^–1 and 41 mA h g^–1 at low temperatures (−10 °C and −20 °C, respectively). Finally, it is concluded that compared to high-metal-loading electrocatalysts, the iridium single-atom electrocatalyst (Li₂O/Ir/N-PAQR SAC) with low metal loading shows excellent electrochemical performance.

The assembly of anisotropic nanoparticles into closely packed structures results in unique functionalities. Herein, we report a 3D multilayer vertical assembly of worm-shaped Au nanoparticles using a carefully regulated evaporation-induced deposition method. With the evaporation of the nanoworm (NW) suspension, the concentration of NWs in the suspension gradually increases, which generates a balance between electrostatic interactions and entropically driven attraction to produce multilayer vertical assemblies. These assemblies exhibit enhanced surface-enhanced Raman scattering (SERS) signals due to the presence of a high concentration of hotspots. Moreover, in contrast to nanorods, the bent morphology of NWs creates pores in the vertical assembly, enabling the analyte molecule to penetrate the assembly and access hotspots. Picomolar to micromolar concentrations of rhodamine 6G (R6G) were detected with the NW assembly-based SERS substrate with excellent linearity and uniformity of the signal with a spot-to-spot relative standard deviation (RSD) of only 8.9%. The SERS substrates were also employed for trace detection of ammonium nitrate, which is a well-known constituent of homemade explosives. Our method of producing multilayer vertical assemblies of NWs is simple, highly sensitive, stable, and reproducible for making effective SERS sensors for the quantitative detection of analytes.

The ultrasound microbubbles modified with the nanomaterial GO not only allow real-time monitoring of liver blood flow for disease diagnosis but also serve as drug delivery carriers, offering the dual benefits of diagnostic imaging and targeted therapy. This presents a highly promising strategy for the integrated diagnosis and treatment of hepatocellular carcinoma (HCC) patients. In this study, L-theanine (TH), a natural polyphenol with antioxidant, and antitumor, was used as a “green” reducing agent for graphene oxide (GO) to prepare nanoscale reduced graphene oxide (rGO-TH), which was then blended with SonoVue microbubbles to prepare composite microbubbles (SV@rGO-TH MBs) for the integrated diagnosis and treatment of HCC. The SV@rGO-TH MBs remain stable at higher Mechanical Index (MI), thereby enhancing contrast-enhanced ultrasound(CEUS) imaging effects and improving the accuracy of disease diagnosis. SV@rGO-TH MBs show significant antitumor activity, inhibiting HepG2 cancer cell growth in vivo and in vitro. Furthermore, combined with ultrasound irradiation, nanoscale rGO-TH more easily penetrates the vascular walls and accumulates in tumor tissues, enhancing the antitumor effect. Our research demonstrates that SV@rGO-TH MBs are a safe and effective ultrasound contrast agent (UCA) for the integrated diagnosis and treatment of HCC, providing insights for the early diagnosis and precise treatment of tumors.

Ceramic-based artificial bones that remain in the body for extended periods must exhibit high mechanical stability. However, the inherent brittleness of ceramics makes it difficult to ensure their long-term stability in vivo. In our previous work, we enhanced the damage tolerance of bulk calcium phosphate (CaP) ceramics by controlling the direction of crack propagation through lamellar structures. Although this material was compositionally suitable for artificial bone applications, its insufficient strength limited its practical use. Therefore, in this study, we developed an artificial bone composite with enhanced crack propagation control by incorporating a nanoscale lamellar-structured CaP phase into zirconia, a ceramic known for its high strength and toughness. The resulting composite features a controlled structure where hydroxyapatite and pyrolytic carbon form nanoscale lamellar structures at the grain boundaries of spherical tetragonal zirconia. The bending strength of this composite was found to be 360 MPa, which is significantly higher than that of dense hydroxyapatite sintered bodies, which are typical nonbiodegradable artificial bone materials. When a crack developed in this composite by indentation test, the damaged part detached. No evident cracks were found after the test, and the material as a whole maintained its integrity. This unique property is likely attributed to the nanoscale lamellar structures at the grain boundaries. Further, in vitro tests conducted using MC3T3-E1 cells confirmed that the composite exhibited no apparent cytotoxicity. Our results indicate that the developed composite can be potentially used to prepare novel nonbiodegradable artificial bone material with excellent long-term mechanical stability in vivo.

Diabetic infected wounds pose a significant challenge due to their refractoriness and potential for serious complications. Conventional treatment strategies primarily rely on antibiotics, which not only contribute to drug resistance but also pose risks of systemic toxicity. Photodynamic therapy (PDT) has emerged as a promising method but suffers from limited effectiveness against Gram-negative bacteria or high material toxicity. For example, quaternary ammonium salts and residual photosensitizers can produce persistent phototoxicity after the antibacterial process, exacerbating the inflammatory response in diabetic wounds and hindering tissue repair. To address these limitations, we developed an innovative zwitterionic pH-responsive polyurethane nanoparticle (PU NP) platform that integrates aggregation-induced emission (AIE) photosensitizers and cinnamaldehyde for targeted and efficient antibacterial treatment. Cinnamaldehyde is released in the bacterial infection microenvironment, synergistically enhancing ROS production with the photosensitizers under light conditions. The multifunctional nanoplatform significantly improves antibacterial efficiency while minimizing off-target toxicity, potential toxicity, and inflammatory response risks. Furthermore, the PU NP system demonstrates the ability to regulate T cell activation and migration in mouse wound tissues, thus optimizing the T cell immune microenvironment. This innovative approach holds promise for the precise treatment of diabetic infected wounds and has the potential to overcome the limitations of current photodynamic therapy, accelerating its clinical translation.