Nano Research最新文献

The rapid quantification of hydroxyl radical (·OH) in real samples is a great challenge due to its highly reactive nature and the potential interferences from other coexisting reactive oxygen species (ROS). Herein, a chemiluminescence (CL) probe (ox-CDs) was rationally developed for the detection of ·OH through controlled oxidation treatment of original CDs (o-CDs) with H₂O₂. Post-oxidation of CDs can reduce the surface defects or functional groups on the CDs, exposing reactive sites capable of effectively reacting with ·OH. The chemical energy generated from redox reaction between ·OH and the ox-CDs can be efficiently utilized to generate strong and selective CL responses to ·OH without interferences from other ROS. Thus, a highly selective and sensitive CL method with a linear range from 0.01 to 150 μM and a detection limit of 3 nM was developed, which was successfully applied for monitoring the ·OH production from cigarette and mosquito coil smoke.

The selective oxidation of hydrocarbons can be used to produce oxygen-containing functional compounds such as alcohols, aldehydes or ketones and its efficient and green conversion lies in the development of efficient catalysts that activate C-H bonds and O₂ simultaneously. In this work, the bimetallic organic framework (CoMnBDC) material with morphology of stacked nanosheets was synthesized using terephthalic acid as ligands to coordinate with Co²⁺ and Mn²⁺ cations under solvothermal conditions. As revealed by spectroscopic characterizations, the electron transfer from Mn to Co in the CoMnBDC resulted in the reduction of the Co average oxidation state and increase of the Mn average oxidation state. The CoMnBDC nanosheets were used as catalyst in catalytic oxidation of ethylbenzene, in which the redox effect promotes the effective electron transfer, the activation of O₂ and benzyl C-H bond. The 96.2% conversion of ethylbenzene and 98.0% selectivity towards acetophenone could be obtained with oxygen as sole oxidant and solvent-free condition. The excellent catalytic performance is related to the structure of CoMnBDC and is also the best when compared with reported results. Various types of aromatic hydrocarbons containing benzyl C-H bonds can be effectively oxidized by CoMnBDC to produce corresponding ketone products. The density functional theory (DFT) calculation revealed that the redox effect leads to the relative enrichment of electrons on Co in CoMnBDC, which is conducive to the activation of O₂; Mn with higher oxidation state is beneficial for the adsorption of ethylbenzene and activation of C-H bonds. The CoMnBDC has a lower energy barrier for transition state, making it easier for the ethylbenzene oxidation to produce acetophenone.

The bimetallic nickel-cobalt phosphide (NiCoP) has been confirmed as an efficient electrocatalyst in water splitting. But little attention is paid to the selectivity and affinity of metal sites on hydrogen evolution reaction (HER) and oxygen evolution reaction (OER). Herein, we report a trace-Zn-doping (2.18 wt.%) NiCoP (Zn-NiCoP) whereby the nanoparticles self-aggregated to form elongated nanoneedles. We discover that both Co and Ni sites can be replaced by Zn. The Co substitution improves HER, while the Ni substitution dramatically reduces the energy barrier of the rate-determining step (*O → *OOH). The negative shift of d-band centers after Zn doping ameliorates the intermediate desorption. Therefore, Zn-NiCoP demonstrates superior electrocatalytic activity with overpotentials of 48 and 240 mV for HER and OER at 10 and 50 mA·cm⁻², respectively. The cell voltage with Zn-NiCoP as both anode and cathode in water splitting was as low as 1.35 V at 10 mA·cm⁻².

In 2023, the Nobel Prize in Chemistry was awarded to Bawendi, Brus, and Ekimov, three scientists who have made great contributions to the discovery and synthesis of quantum dots (QDs), heralding a new era for these nanomaterials. The inception of QDs dates back more than 40 years, during which the theory of QDs has been continuously refined, the manufacturing techniques have significantly flourished, and the applications have largely expanded. Recently, QDs have become important optical devices, playing key roles in numerous fields such as display, energy, and biomedical applications. To celebrate the outstanding achievements of QDs over the years, we dedicate this paper to QDs. In the information field, QDs have been extensively utilized to design devices related to domains like transmission and storage, achieving many breakthroughs in performance. This paper proposes a comprehensive set of methodologies and paradigms for designing information systems using QDs. The proposed approach embodies two characteristics of QDs: 1) QDs play a central role in every aspect of the system and possess the capability to construct an all-quantum-dot (All-QD) information system. 2) QDs possess tunability and wavelength flexibility, which can significantly enhance the information density. Finally, we construct a prototype model of an All-QD information system and validate its feasibility through simulation. We believe that with the continued development of quantum dot (QD) technology, the realization of an All-QD information system is on the horizon.

Transition metal catalyzed chemical vapor deposition (CVD) is considered as the most promising approach to synthesize highquality graphene films, and low-temperature growth of defect-free graphene films is long-term challenged because of the high energy barrier for precursor dissociation and graphitization. Reducing the growth temperature can also bring advantages on wrinkle-free graphene films owing to the minimized thermal expansion coefficient mismatch. This work focuses on density functional theory (DFT) calculations of the carbon source precursor with hydroxyl group, especially CH₃OH, on low-temperature CVD growth of graphene on Cu and CuNi substrate. We calculated all the possible cleavage paths for CH₃OH on transition metal substrates. The results show that, firstly, the cleavage barriers of CH₃OH on transition metal substrates are slightly lower than those of CH₄, and once CO appears, it is difficult to break the C-O bond. Secondly, the CO promotes a better formation and retention of perfect rings in the early stage of graphene nucleation and reduces the edge growth barriers. Thirdly, these deoxidation barriers of CO are reduced after CO participates in graphene edge growth. This paper provides a strategy for the lowtemperature growth of wrinkles-free graphene on transition metal substrates using CH₃OH.

Direct photopatterning is a powerful strategy for patterning colloidal quantum dots (QDs) for their integration in various electronic and optoelectronic devices. However, ultraviolet (UV) exposure required for QD patterning, especially those with short wavelength (e.g., deep UV light), can degrade the photo-, and electroluminescence, and other properties of patterned QDs. Here we develop a photosensitizer-assisted approach for direct photopatterning of QDs with h-line (centered at 405 nm) UV light and better preservation of their luminescent properties. This approach uses a photosensitizer that can absorb the h-line UV light and transfer the energy to activate bisazide-based crosslinkers via Dexter energy transfer. Uniform, high-resolution (smallest feature size, 2 µm), and full-color patterns of red, green, and blue QD layers can be achieved. The patterned QD layers maintain up to ∼ 90% of their original photoluminescent quantum yields, comparing favorably with those (< 60%) of QDs patterned without photosensitizers. We further extended the strategy to the direct three-dimensional (3D) printing of QDs. This photosensitizer-assisted approach offers a new way for direct two-dimensional (2D) photopatterning and 3D printing of colloidal QDs, with implications in building high-performance QD optoelectronic devices.

Compared to nanostructured Si/C materials, micro-sized Si/C anodes for lithium-ion batteries (LIBs) have gained significant attention in recent years due to their higher volumetric energy density, reduced side reactions and low costs. However, they suffer from more severe volume expansion effects, making the construction of stable micro-sized Si/C anode materials crucial. In this study, we proposed a simple wet chemistry method to obtain porous micro-sized silicon (μP-Si) from waste AlSi alloys. Then, the μP-Si@carbon nanotubes (CNT)@C composite anode with high tap density was prepared by wrapping with CNT and coated with polyvinylpyrrolidone (PVP)-derived carbon. Electrochemical tests and finite element (FEM) simulations revealed that the introduction of CNTs and PVP-derived carbon synergistically optimize the stability and overall performance of the μP-Si electrode via construction of tough composite interface networks. As an anode material for LIBs, the μP-Si@CNT@C electrode exhibits boosted reversible capacity (∼ 3500 mAh·g⁻¹ at 0.2 A·g⁻¹), lifetime and rate performance compared to pure μP-Si. Further full cell assembly and testing also indicates that μP-Si@CNT@C is a highly promising anode, with potential applications in future advanced LIBs. It is expected that this work can provide valuable insights for the development of micro-sized Si-based anode materials for high-energy-density LIBs.

Optimizing the catalytic activity and stability of molybdenum disulfide (MoS2) towards alkaline hydrogen evolution reaction (HER) is significant for sustaining green hydrogen. A moderate localized electronic structure of active sites plays a crucial role in determining the activity and stability of the catalysts, yet how to construct such localized electronic structure still remains indeterminacy. Enlightened by theoretical prediction, herein, the introduction of both single-atom Re and the adjacent S vacancy in MoS₂ (denoted as Re-MoS₂-Vs) exhibits collaborative effect on regulating the localized electronic structure of active sites (viz. Re-(S, Vs)-Mo). Such regulated electronic structure helps to decrease the energy barrier of the water dissociation and optimize hydrogen adsorption energy for enhancing alkaline HER performance. Most importantly, Mo-S bonds in the above local Re-(S, Vs)-Mo configurations are also strengthened for preventing the leaching of Mo and S atoms and then ensuring the long-time stability. Consequently, the deliberately designed Re-MoS₂-Vs with a Re coordination number of ~ 5.0 is experimentally verified to exhibit a comparable electrocatalytic performance and robust operational stability over 120 h. This strategy provides a promising guidance for modulating the electronic structure of MoS2 based catalysts via double-tuning atomic-scale local configuration for HER applications.

Integrating hierarchical plasmonic cavities into photocatalysis offers a promising avenue for expanding the light utilization range to cover the entire solar spectrum. However, fabricating these nanostructures with seamless size transitions for a wide plasmon resonant range remains technically challenging, requiring precise nanofabrication control and often relying on expensive and laborious techniques like e-beam lithography and reactive ion etching. Herein, a one-step forming strategy was explored to fabricate simple yet hierarchical plasmonic cavities featuring the surface nanodome array-integrated plasmonic Fabry–Pérot cavity through a facile large-area nanoimprinting method. This design leverages a uniform feature size and periodic arrangement to broaden the light utilization range of TiO₂ across the entire solar spectrum (200–2500 nm). It consists of an upper nanodome array cavity with vertically continuous graded sizes for broadband absorption (200–1500 nm), coupled with a bottom plate cavity that enlarges the overall cavity size to extend the range to 2500 nm. Remarkably, simply adjusting the thickness of the plate cavity can tune the resonant position, eliminating the need for expensive mold modifications. When combined with TiO₂, this hierarchical plasmonic cavity significantly enhances the photocatalytic hydrogen evolution rate to 36.3 µmol/h, achieving a remarkable 9.8-fold increase compared to pure TiO₂ under full-spectrum illumination. This approach offers a convenient and inexpensive alternative to sophisticated nanofabrication techniques for large-area hierarchical plasmonic cavities with broadband plasmon resonance to enhance the photocatalytic hydrogen evolution.

Three-dimensional (3D) host materials for lithium metal anodes (LMAs) have gained attention because they can mitigate volume expansion and local current density through their large surface area and suppress the dendritic growth of lithium. Recent research on 3D host materials has focused on conductive materials; however, the benefits of 3D host materials cannot be fully utilized because lithium deposition begins at the top of the structure. Herein, we fabricate SiO₂-TiO₂ composite microspheres with bimodal pore structures (bi-SiTiO) by simple spray pyrolysis. These microspheres effectively store lithium within the structure from the bottom of the electrode while preventing lithium dendrite formation. Focused ion beam-scanning transmission electron microscopy (FIB-STEM) analysis reveals that the lithiophilic properties of composite microspheres enhanced their effectiveness in storing lithium, with small pores acting as “lithium-ion sieves” for a uniform lithium-ion flux and large pores that provide sufficient volume for lithium deposition. The bi-SiTiO composite microspheres exhibit a high Coulombic efficiency of 98.5% over 200 cycles at 2.0 mA·cm⁻² when operated in a lithium half-cell. With a high lithium loading of 5.0 mAh·cm⁻², the symmetrical cell of the bi-SiTiO electrode sustains more than 900 h. A full cell coupled with an LiNi_0.8Co_0.1Mn_0.1O₂ (NCM811) cathode also exhibits enhanced electrochemical properties in terms of cycling stability and rate capability.