An Online Nanoinformatics Platform Empowering Computational Modeling of Nanomaterials by Nanostructure Annotations and Machine Learning Toolkits.

Modern nanotechnology has generated numerous datasets from in vitro and in vivo studies on nanomaterials, with some available on nanoinformatics portals. However, these existing databases lack the digital data and tools suitable for machine learning studies. Here, we report a nanoinformatics platform that accurately annotates nanostructures into machine-readable data files and provides modeling toolkits. This platform, accessible to the public at https://vinas-toolbox.com/, has annotated nanostructures of 14 material types. The associated nanodescriptor data and assay test results are appropriate for modeling purposes. The modeling toolkits enable data standardization, data visualization, and machine learning model development to predict properties and bioactivities of new nanomaterials. Moreover, a library of virtual nanostructures with their predicted properties and bioactivities is available, directing the synthesis of new nanomaterials. This platform provides a data-driven computational modeling platform for the nanoscience community, significantly aiding in the development of safe and effective nanomaterials.

Programmable Reconfiguration of Supramolecular Bottlebrush Block Copolymers: From Solution Self-Assembly to Co-Crystallization-Assistant Self-Assembly.

Achieving structural reconfiguration of supramolecular bottlebrush block copolymers toward topological engineering is of particular interest but challenging. Here, we address the creation of supramolecular architectures to discover how assembled topology influences the structured aggregates, combining hydrogen-bonded (H-bonded) bottlebrush block copolymers and electrostatic interaction induced polymer/inorganic eutectics. We first design H-bonding linear-brush block copolymer P(NBDAP-co-NBC)-b-P(NBPEO), bearing linear block P(NBDAP-co-NBC) (poly(norbornene-terminated diaminopyridine-co-norbornene-terminated hexane)) with pendant H-bonding DAP (diaminopyridine) motifs, and PEO (poly(ethylene oxide)) densely grafted P(NBPEO) brush block. Thanks to H-bonding association between DAP and thymine (Thy), incorporation of Thy-functionalized polystyrene (Thy-PS) enables solution self-assembly and formation of H-bonded bottlebrush block copolymers, generating augmented nanospheres with increasing Thy-PS amount. Noteworthy that integration of inorganic cluster silicotungstic acid (STA) to P(NBC-co-NBDAP)-b-P(NBPEO), endows the formation of PEO/STA eutectic core. Therefore, co-crystallization-assistant self-assembly at the interfaces of polymeric, inorganic and supramolecular chemistry is realized, reflecting multi-stage morphology transformation from hexagonal platelets, needle-like, curved rod-like micelles, finally to end-to-end closed rings, by gradually increasing Thy-PS while fixing STA content. Interestingly, such solution self-assembly to co-crystallization-assistant self-assembly strategy not only endows unique nanostructure transition, also induce in-to-out switch of PS domains. These findings clearly provide unique methodology towards programmable fabrication of geometrical objects promising in smart materials.

Targeted-lung delivery of bardoxolone methyl using PECAM-1 antibody-conjugated nanostructure lipid carriers for the treatment of lung inflammation.

The effective treatment of acute lung injury (ALI) remains a significant challenge. Patients with ALI demonstrate an abundance of proinflammatory mediators in both bronchoalveolar lavage fluid (BALF) and circulating plasma. Bardoxolone methyl (BM) is a semi-synthetic triterpenoid derived from oleanolic acid, a natural product known for its ability to inhibit proinflammatory signaling. GSDMD is a signaling protein involved in pyroptosis, a form of programmed cell death. It has been reported that its upstream proteins play a role in the pathogenesis of ALI. However, there is currently no research examining whether the effect of BM on the occurrence and development of ALI is associated with changes in GSDMD protein. In this study, we prepared nanostructured lipid carriers loaded with BM and conjugated with anti-PECAM-1 antibody (PECAM@BM NLCs). PECAM@BM NLCs were designed to specifically bind to pulmonary vascular endothelial cells that highly express the PECAM-1 receptors. We also aimed to investigate the protective effects of PECAM@BM NLCs on ALI and elucidate the underlying molecular mechanisms. The results demonstrated that PECAM@BM NLCs accumulated in the lung tissues and significantly alleviated the inflammatory injury of ALI. This was evidenced by the changes in the lung wet/dry ratio, the total protein concentration, proinflammatory cytokines in BALF, and the histopathological progress. Additionally, we elucidated that PECAM@BM NLCs had the ability to inhibit the assembly of NLRP3 inflammasome and pro-caspase-1 complex, thereby suppressing the induction of pyroptosis. This mechanism resulted in the inhibition of N-terminal GSDMD expression and effectively prevented the progression of ALI.

Cellulose Surface Nanoengineering for Visualizing Food Safety.

Food safety is vital to human health, necessitating the development of nondestructive, convenient, and highly sensitive methods for detecting harmful substances. This study integrates cellulose dissolution, aligned regeneration, in situ nanoparticle synthesis, and structural reconstitution to create flexible, transparent, customizable, and nanowrinkled cellulose/Ag nanoparticle membranes (NWCM-Ag). These three-dimensional nanowrinkled structures considerably improve the spatial-electromagnetic-coupling effect of metal nanoparticles on the membrane surface, providing a 2.3 × 108 enhancement factor for the surface-enhanced Raman scattering (SERS) effect for trace detection of pesticides in foods. Notably, the distribution of pesticides in the apple peel and pulp layers is visualized through Raman imaging, confirming that the pesticides penetrate the peel layer into the pulp layer (∼30 µm depth). Thus, the risk of pesticide ingestion from fruits cannot be avoided by simple washing other than peeling. This study provides a new idea for designing nanowrinkled structures and broadening cellulose utilization in food safety.

Quantitative selection of sample structures in small-angle scattering using Bayesian methods.

Small-angle scattering (SAS) is a key experimental technique for analyzing nanoscale structures in various materials. In SAS data analysis, selecting an appropriate mathematical model for the scattering intensity is critical, as it generates a hypothesis of the structure of the experimental sample. Traditional model selection methods either rely on qualitative approaches or are prone to overfitting. This paper introduces an analytical method that applies Bayesian model selection to SAS measurement data, enabling a quantitative evaluation of the validity of mathematical models. The performance of the method is assessed through numerical experiments using artificial data for multicomponent spherical materials, demonstrating that this proposed analysis approach yields highly accurate and interpretable results. The ability of the method to analyze a range of mixing ratios and particle size ratios for mixed components is also discussed, along with its precision in model evaluation by the degree of fitting. The proposed method effectively facilitates quantitative analysis of nanoscale sample structures in SAS, which has traditionally been challenging, and is expected to contribute significantly to advancements in a wide range of fields.

Cellulose binary coatings with spherical envelope structure via structure rearrangement in ball milling for integrated radiative cooling-electricity generation.

Passive daytime radiative cooling is a zero-energy consumption cooling technology, which can dissipate heat to outer space via infrared radiation. Recently, coupling radiative cooling technology and thermoelectric devices to generate electricity has attracted much attention. However, existing radiative cooling integrated thermoelectric devices still suffer from low-temperature gradient and output voltage. Here, based on the Mie scattering and internal reflection enhancing principle, an impact-inducing geometry reconstruction approach was proposed to fabricate hierarchical nanostructured cellulosic coatings with good daytime cooling performance to achieve stable electricity generation function, which can be realized by using a scalable and facile wet ball milling technology. Guided by the theoretical simulations of the finite difference time domain method (FDTD), the cellulose and TiO2 nanoparticles can assemble into spherical envelope structured coatings drying by the shear, impact, and friction interaction in the ball milling process, dramatically enhancing the Mie scattering and internal reflection of coatings. The cellulosic coatings exhibit sunlight reflectivity of 0.962 and infrared emissivity of 0.94, resulting in a daytime radiative cooling efficiency of 5.9 °C under direct sunlight. Energy Plus stimulation demonstrated 35 % cooling energy and 468.9 kWh of cooling energy can be saved annually in China. Meanwhile, this cellulosic coating-based thermoelectric device can deliver a high voltage output of 150 mV under 1 Sun due to the strong bonding and high-temperature gradient formation (30 °C), which is higher than previous reports. This study will facilitate the development of sustainable power generation device for the goal of green future.

Nanostructure and Dynamics of the Locally Concentrated Ionic Liquid 2:1 (wt:wt) HMIM FAP:TFTFE and HMIM FAP on Graphite and Gold Electrodes as a Function of Potential.

Video-rate atomic force microscopy (AFM) is used to record the near-surface nanostructure and dynamics of one pure ionic liquid (IL), 1-hexyl-3-methylimidazolium tris(pentafluoroethyl)trifluorophosphate (HMIM FAP), and a locally-concentrated IL comprising HMIM FAP with the low viscosity diluent 1,1,2,2-tetrafluoroethyl 2,2,2-trifluoroethyl ether (TFTFE), on highly oriented pyrolytic graphite (HOPG) and Au(111) electrodes as a function of potential. Over the potential range measured (open-circuit potential ± 1 V), different near-surface nanostructures are observed. For pure HMIM FAP, globular aggregates align in rows on HOPG, whereas elongated and worm-like nanostructures form on Au(111). For 2:1 (wt:wt) HMIM FAP:TFTFE, larger and less defined diluent swollen IL aggregates are present on both electrodes. Long-lived near-surface nanostructures for HMIM FAP and the 2:1 (wt:wt) HMIM FAP:TFTFE persist on both electrodes. 2:1 (wt:wt) HMIM FAP:TFTFE mixture diffuses more rapidly than pure HMIM FAP on both electrodes with obviously higher diffusion coefficients on HOPG than on Au(111) due to weaker electrostatic and solvophobic interactions between near-surface aggregates and Stern layer ions. These outcomes provide valuable insights for a wide range of IL applications in interface sciences, including electrolytes, catalysts, lubricants, and sensors.

Solvothermal synthesis of PdCu nanorings with high catalytic performance for alcohol electrooxidation.

Two-dimensional (2D) Pd-based nanostructures with a high active surface area and a large number of active sites are commonly used in alcohol oxidation research, whereas the less explored ring structure made of nanosheets with large pores is of interest. In this study, we detail the fabrication of PdCu nanorings (NRs) featuring hollow interiors and low coordinated sites using a straightforward solvothermal approach. Due to increased exposure of active sites and the synergistic effects of bimetallics, the PdCu NRs exhibited superior catalytic performance in both the ethanol oxidation reaction (EOR) and the ethylene glycol oxidation reaction (EGOR). The mass activities of PdCu NRs for EOR and EGOR were measured at 7.05 A/mg and 8.12 A/mg, respectively, surpassing those of commercial Pd/C. Furthermore, the PdCu NRs demonstrated enhanced catalytic stability, maintaining higher mass activity levels compared to other catalysts during stability testing. This research offers valuable insights for the development of efficient catalysts for alcohol oxidation.

The sensing of circRNA with tetrahedral DNA nanostructure modified microfluidic chip.

BACKGROUND: Circular ribonucleic acids (circRNAs) are a type of covalently closed noncoding RNA with disease-relevant expressions, making them promising biomarkers for diagnosis and prognosis. Accurate quantification of circRNA in biological samples is a necessity for their clinical application. So far, methods developed for detecting circRNAs include northern blotting, reverse transcription quantitative polymerase chain reaction (RT-qPCR), microarray analysis, and RNA sequencing. These methods generally suffer from disadvantages such as large sample consumption, cumbersome process, low selectivity, leading to inaccurate quantification of circRNA. It was thought that the above drawbacks could be eliminated by the construction of a microfluidic sensor. RESULTS: Herein, for the first time, a microfluidic sensor was constructed for circRNA analysis by using tetrahedral DNA nanostructure (TDN) as the skeleton for recognition probes and target-initiated hybridization chain reaction (HCR) as the signal amplification strategy. In the presence of circRNA, the recognition probe targets the circRNA-specific backsplice junction (BSJ). The captured circRNA then triggers the HCR by reacting with two hairpin species whose ends were labeled with 6-FAM, producing long DNA strands with abundant fluorescent labels. By using circ_0061276 as a model circRNA, this method has proven to be able to detect circRNA of attomolar concentration. It also eliminated the interference of linear RNA counterpart, showing high selectivity towards circRNA. The detection process can be implemented isothermally and does not require expensive complicated instruments. Moreover, this biosensor exhibited good performance in analyzing circRNA targets in total RNA extracted from cancer cells. SIGNIFICANCE: This represents the first microfluidic system for detection of circRNA. The biosensor showed merits such as ease of use, low-cost, small sample consumption, high sensitivity and specificity, and good reliability in complex biological matrix, providing a facile tool for circRNA analysis and related disease diagnosis in point-of care application scenes.

Immunochromatographic Strip Based on Tetrahedral DNA Immunoprobe for the Detection of Aflatoxin B1 in Rice Bran Oil.

Aflatoxin B1 (AFB1), a widespread contaminant in food and feeds, poses a threat to the health of animals and humans. Consequently, it is significant to develop a rapid, precise and highly sensitive analytical method for the detection of AFB1. Herein, we developed an immunochromatographic strip (ICS) based on a tetrahedral DNA (TDN) immunoprobe for AFB1 determination in rice bran oil. Three sizes of TDN immunoprobes (AuNP-TDN13bp-mAb, AuNP-TDN17bp-mAb, AuNP-TDN26bp-mAb) were constructed, and the performance of these three immunoprobes, including the effective antibody labeling density and immunoaffinity, was measured and compared with that of the immunoprobe (AuNP-mAb) developed using the physical adsorption method. Subsequently, the optimal TDN immunoprobe, namely AuNP-TDN13bp-mAb, was selected to prepare the immunochromatographic strip (ICS) for the qualitative and quantitative detection of AFB1 in rice bran oil. The visual limits of detection (vLODs) of the ICS based on AuNP-TDN13bp-mAb and AuNP-mAb were 0.2 ng/mL and 2 ng/mL, with scanning quantitative limits (sLOQs) of 0.13 ng/mL and 1.4 ng/mL, respectively. The ICS demonstrated a wide linear range from 0.02 ng/mL to 0.5 ng/mL, with good specificity, accuracy, precision, repeatability, and stability. Moreover, a high consistency was observed between the constructed ICS and ultra-high-performance liquid chromatography (UPLC) in the quantification of AFB1. The results indicated that the introduction of TDN was beneficial for promoting efficient antibody labeling, protecting the bioactivity of immunoprobes, and increasing the sensitivity of detection, which would provide new perspectives for the achievement of the highly sensitive detection of mycotoxins.

Increasing the Strength and Impact Toughness of Carbon Steel Using a Nanosized Eutectoid Resulting from Time-Controlled Quenching.

High-carbon steels are normally used as tool materials. The use of such steels for construction is limited due to their increased brittleness and poor weldability. However, it appears that high-carbon steels possess certain hidden reserves for enhanced plasticity and strength if properly heat-treated. An unconventional heat treatment was applied to carbon eutectoid steel (0.8 wt.% C) in order to increase its strength and impact toughness simultaneously. Samples for tensile and impact testing were held at 800 °C for different time ranges from 3 min to 9 min with subsequent cooling in oil. It was established that for each type of sample, an optimal holding time exists that is responsible for increased strength and high impact toughness. The hardness and microhardness levels of the surface and under-surface regions of the samples reached 390 HV after optimal heat treatment. An X-ray revealed a shift of the (211)α-peak to the lower 2-theta angles after heat treatment with the optimal holding time; this indicates an increase in carbon content in alpha solid solutions of approximately 0.12 wt.%. Thus, a nanostructured mixture of low-carbon martensite and thin cementite plates is formed in the under-surface region of carbon eutectoid steel after heat treatment, with a controlled holding time at the austenitizing temperature.

Influence of Substrate Location and Temperature Variation on the Growth of ZnO Nanorods Synthesized by Hot Water Treatment.

Hot water treatment (HWT) is a versatile technique for synthesizing metal oxide nanostructures (MONSTRs) by immersing metal substrates in hot water, typically in glass beakers. The proximity of substrates to the heat source during HWT can influence the temperature of the substrate and subsequently impact MONSTR growth. In our study, zinc (Zn) substrates underwent HWT at the base of a glass beaker in contact with a hot plate and at four different vertical distances from the base. While the set temperature of deionized (DI) water was 75.0 °C, the substrate locations exhibited variations, notably with the base reaching 95.0 °C. Scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD), and Raman spectroscopy showed stoichiometric and crystalline zinc oxide (ZnO) nanorods. ZnO rods on the base, exposed to higher temperatures, displayed greater growth in length and diameter, and higher crystallinity. Nanorods with increasing vertical distances from the base exhibited a logarithmic decrease in length despite identical temperatures, whereas their diameters remained constant. We attribute these findings to crucial HWT growth mechanisms like surface diffusion and "plugging", influenced by temperature and water flow within the beaker. Our results provide insights for optimizing synthesis parameters to effectively control MONSTR growth through HWT.

Ion-Ion Selectivity of Synthetic Membranes with Confined Nanostructures.

Synthetic membranes featuring confined nanostructures have emerged as a prominent category of leading materials that can selectively separate target ions from complex water matrices. Further advancements in these membranes will pressingly rely on the ability to elucidate the inherent connection between transmembrane ion permeation behaviors and the ion-selective nanostructures. In this review, we first abstract state-of-the-art nanostructures with a diversity of spatial confinements in current synthetic membranes. Next, the underlying mechanisms that govern ion permeation under the spatial nanoconfinement are analyzed. We then proceed to assess ion-selective membrane materials with a focus on their structural merits that allow ultrahigh selectivity for a wide range of monovalent and divalent ions. We also highlight recent advancements in experimental methodologies for measuring ionic permeability, hydration numbers, and energy barriers to transport. We conclude by putting forth the future research prospects and challenges in the realm of high-performance ion-selective membranes.

Dealing with plasmonic crystal biosensors: Sensitivity assessment of nanodisks/nanoholes arrayed plasmonic system for label-free DNA detection.

Label-free optical deoxyribonucleic acid (DNA) sensing with arrayed plasmonic nanostructures (plasmonic crystals) is a promising technology for biomedical diagnosis and bioanalytical science. Plasmonic biosensors can detect target biomolecules by utilizing the shift in plasmonic resonance caused by changes in the surrounding refractive index (RI) attributed to the capture of target biomolecules using a recognizer. Conventional explanations for the sensitivity of plasmonic crystals are based on bulk (BRIS) and surface RI sensitivities (SRIS) for basic plasmonic nanoparticles despite their unique properties such as surface lattice resonances (SLRs), wherein localized surface plasmons (LSPs) cooperatively oscillate with their pitch. Therefore, investigating the sensitivity of SLRs is imperative for improving sensing performance. In this study, the sensitivity of adenomatous polyposis coli (APC) gene-related DNA hybridization detection of complementary plasmonic crystals composed of nanodisks (PNDs) on or under plasmonic nanoholes (PNHs) was investigated considering the SLR properties. The BRIS was measured using the conventional definition of the peak wavelength shift per unit RI increment (nm/RIU) followed by the SRIS measurement using the layer-by-layer method. The BRIS and SRIS measurements reflect the practical sensitivity for DNA detection. PNHs had higher sensitivity than PNDs, with a limit of detection of 0.30 nM. Further, only the SLR-based mode responded to localized RI changes because of DNA hybridization, whereas both the LSPs- and SLR-based modes responded to uniform RI changes caused by layer-by-layer coating. Our investigation will open up possibilities and opportunities for plasmonic crystal biosensors.

Aptasensor based on gold nanostructure-decorated 2D Cu metal-organic framework nanosheets for highly sensitive and specific electrochemical lipopolysaccharide detection.

Detecting lipopolysaccharide (LPS) using electrochemical methods is significant because of their exceptional sensitivity, simplicity, and user-friendliness. Two-dimensional metal-organic framework (2D-MOF) that merges the benefits of MOF and 2D nanostructure has exhibited remarkable performance in constructing electrochemical sensors, notably surpassing traditional 3D-MOFs. In this study, Cu[tetrakis(4-carboxylphenyl)porphyrin] (Cu-TCPP) and Cu(tetrahydroxyquinone) (Cu-THQ) 2D nanosheets were synthesized and applied on a glassy carbon electrode (GCE). The 2D-MOF nanosheets, which serve as supporting layers, exhibit improved electron transfer and electronic conductivity characteristics. Subsequently, the modified electrode was subjected to electrodeposition with Au nanostructures, resulting in the formation of Au/Cu-TCPP/GCE and Au/Cu-THQ/GCE. Notably, the Au/Cu-THQ/GCE demonstrated superior electrochemical activity because of the 2D morphology, redox ligand, dense Cu sites, and improved deposition of flower-like Au nanostructure based on Cu-THQ. The electron transfer specific surface area was increased by the improved deposition of Au nanostructures, which facilitates enriched binding of LPS aptamer and significantly improved the detection performance of Apt/Au/Cu-THQ/GCE electrochemical aptasensor. The limit of detection for LPS reached 0.15 fg/mL with a linear range of 1 fg/mL - 100 pg/mL. The proposed aptasensor demonstrated the ability to detect LPS in serum samples with satisfactory accuracy, indicating significant potential for clinical diagnosis.

Advancing Flexible Sensors through On-Demand Regulation of Supramolecular Nanostructures.

The evolution of flexible sensors heavily relies on advances in soft-material design and sensing mechanisms. Supramolecular chemistry offers a powerful toolbox for manipulating nanoscale and molecular structures within soft materials, thus fostering recent advancements in flexible sensors and electronics. Supramolecular interactions have been utilized to nanoengineer functional sensing materials or construct chemical sensors with lower cost and broader targets. In this perspective, we will highlight the use of supramolecular interactions to regulate and optimize nanostructures within functional soft materials and illustrate their importance in expanding the nanocavities of bioreceptors for chemical sensing. Overall, a bridge between tissue-mimicking flexible sensors and cell-mimetic supramolecular chemistry has been built, which will further advance human healthcare innovation.

Gold nanostructures on polyelectrolyte-brush-modified cellulose membranes as a synergistic platform for uric acid detection.

In this study, we present a convenient approach utilizing gold nanostructures coated cellulose membrane for the quantification of uric acid in an aqueous solution. The synthesis of system was achieved by functionalizing cellulose membrane with poly[2-(methacryloyloxy)ethyl]trimethylammonium chloride (PMETAC) and cross-linked with ethylene glycol dimethacrylate (EGDMA). FT-IR and XPS confirm the formation of PMETAC and PMETAC/EGDMA on the cellulose. The fabricated substrates were exposed to tetrachloroaurate solution, then reduced by NaBH4. We have systematically investigated the catalytic oxidation of 3,3',5,5'-tetramethylbenzidine (TMB) by hydrogen peroxide (H2O2) in various pH conditions, absent uric acid, using the fabricated substrates. The colorimetric response-observed through UV-Vis spectroscopy-revealed significant shifts in absorbance at 660 nm, correlating with uric acid concentrations across a range of pH levels. The films exhibited a pronounced color change from green to light yellow in basic to neutral environments and from yellow to dark green under more acidic conditions, demonstrating their potential for high-sensitivity uric acid detection. The assessment of the catalytic films' reusability and stability revealed insights into their enduring performance, identifying opportunities for enhancing material design and functionality for extended applications. This study not only underscores the films' versatile detection capabilities but also emphasizes the importance of pH in tuning the assay's sensitivity and specificity.

Texture tomography, a versatile framework to study crystalline texture in 3D.

Crystallographic texture is a key organization feature of many technical and biological materials. In these materials, especially hierarchically structured ones, the preferential alignment of the nano constituents heavily influences the macroscopic behavior of the material. To study local crystallographic texture with both high spatial and angular resolution, we developed Texture Tomography (TexTOM). This approach allows the user to model the diffraction data of polycrystalline materials using the full reciprocal space of the crystal ensemble and describe the texture in each voxel via an orientation distribution function, hence it provides 3D reconstructions of the local texture by measuring the probabilities of all crystal orientations. The TexTOM approach addresses limitations associated with existing models: it correlates the intensities from several Bragg reflections, thus reducing ambiguities resulting from symmetry. Further, it yields quantitative probability distributions of local real space crystal orientations without further assumptions about the sample structure. Finally, its efficient mathematical formulation enables reconstructions faster than the time scale of the experiment. This manuscript presents the mathematical model, the inversion strategy and its current experimental implementation. We show characterizations of simulated data as well as experimental data obtained from a synthetic, inorganic model sample: the silica-witherite biomorph. TexTOM provides a versatile framework to reconstruct 3D quantitative texture information for polycrystalline samples; it opens the door for unprecedented insights into the nanostructural makeup of natural and technical materials.

Real biofuel and fossil-fuel soot combustion activities in active and passive regeneration of diesel/gasoline particulate filters under different O2/NOx concentrations.

In this work, we aim to investigate and compare the combustion reactivities of real biofuel soot and fossil-fuel soot in the active and passive regeneration conditions of DPF and GPF through temperature-programmed oxidation (TPO). Higher reactivity of biofuel soot is achieved even under GPF conditions with extremely low oxygen concentration (~ 1%), which provides a great potential for low-temperature regeneration of GPF. Such a result is mainly attributed to the low graphitization and less surface C = C groups of biofuel soot. Unfortunately, the presence of high-content ashes (~ 47%) and P impurity in real biofuel soot hinder its combustion reactivity. TPO evidences that the O2/NOX-lacking conditions in GPF are key factors to impact the combustion of soot, especially fossil-fuel soot. This work provides some useful information for understanding real biofuel and fossil-fuel soot combustion in GPF and DPF regeneration and further improvement in filter regeneration process.

Cascade Electrocatalytic Nitrate Reduction Reaching 100% Nitrate-N to Ammonia-N Conversion over Cu2O@CoO Yolk-Shell Nanocubes.

The electroreduction of nitrate to ammonia via a selective eight-electron transfer nitrate reduction reaction offers a promising, low energy consumption, pollution-free, green NH3 synthesis strategy alternative to the Haber-Bosch method. However, it remains a great challenge to achieve high NH4+ selectivity and complete conversion from NO3--N to NH4+-N. Herein, we report ingredients adjustable Cu2O@CoO yolk-shell nanocubes featured with tunable inner void spaces and diverse activity centers, favoring the rapid cascade conversion of NO3- into NO2- on Cu2O and NO2- into NH4+ on CoO. Cu2O@CoO yolk-shell nanocubes exhibit super NH4+ Faradaic efficiencies (>99%) over a wide potential window (-0.2 V to -0.9 V versus RHE) with a considerable NH4+ yield rate of 15.27 mg h-1 cm-2 and fantastic cycling stability and long-term chronoamperometric durability. Cu2O@CoO yolk-shell nanocubes exhibited glorious NO3--N to NH4+-N conversion efficiency in both dilute (500 ppm) and highly concentrated (0.1 and 1 M) NO3- electrolytes, respectively. The nitrate electrolysis membrane electrode assembly system equipped with Cu2O@CoO yolk-shell nanocubes delivers over 99.8% NH4+ Faradaic efficiency at cell voltages of 1.9-2.3 V.