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The mainstream synthesis method for MXene is using aqueous fluorine-containing acidic solutions to eliminate the A-element layers from their MAX phases. However, this strategy is environmentally hazardous and impairs the material performance (e.g., supercapacitor and Li-S batteries) owing to the presence of -F terminations. Herein, we exploit a low-temperature "soft chemistry" approach based on photo-Fenton (P.F.) reaction for the fabrication of F-free Ti

A series of novel botanical active component 4-chromanone derivatives incorporating carboxamide and 1,3,4-thiadiazole thioether moieties were synthesized and evaluated for their in vitro antibacterial and activities antifungal against Xanthomonas axonopodis pv. citri (Xac), Xanthomonas oryzae pv. oryzicolaby (Xoc) and Mucor bainieri (M. bainieri), Mucor fragilis (M. fragilis), Trichoderma atroviride (T. atroviride), respectively. Antibacterial screening results suggested that the target compounds showed moderate to good antibacterial activities against Xac and Xoc, to the contrary, had lower inhibitory effects on M. fragilis, M. bainieri, and T. atroviride. Among the target compounds, compound 6-chloro-N-(5-(methylthio)-1,3,4-thiadiazol-2-yl)-4-oxochromane-2-carboxamide (6f) had the best inhibition rates against Xac (85.15% and 72.41%, respectivelty) and Xoc (95.14% and 82.09%) at 200 and 100 μg/mL, which were superior to Bismerthiazol and Thiodiazole copper. As far as we know, it is the first report on the design, synthesis, and bioactivity evaluation of novel 4-chromanone-derived compounds incorporating carboxamide and 1,3,4-thiadiazole thioether moieties.

The simultaneous engineering of sulfur cathode and Li anode is critical for electrolyte-starved high-energy-density Li-S batteries. Herein, we challenge the conventional wisdom of heterogeneous and homogeneous catalyses in Li-S batteries, the concept of anti-heterogeneous catalysis is proposed to synchronously realize effective LiPS trapping/conversion and protection of Li anode through employing a small amount of non-nucleophilic electrolyte additive of an amidomagnesium halide, hexamethyldisilazide magnesium chloride (HMC). Regulated by the amidomagnesium halide chemistry, over 1000 hours of cycling is realized in Li/Li symmetric cells, revealing superb compatibility of the HMC-incorporated electrolyte with lithium metal. Meanwhile, via elevating the dissociation free-energy barrier of Li+ in LiPS, the liquid HMC catalysts significantly decrease the solubility of lithium ploysulfides and promote the multistep conversion of sulfur electrochemistry, which enable a quasi-solid-state reaction and minimal shuttle effect. Practically, a high energy density of 423 Wh kg-1 with decent cycling stability is achieved in electrolyte-starved pouch cells.

Constructing highly conductive compact sulfur cathode composites with shorter ion diffusivity lengths is vital for achieving comprehensively superior electrochemical performance under a high mass loading condition. Guided by computerization modeling, we, herein, report self-supporting CNTs-VSe2-VOx/S assembly with balanced tortuosity and porosity for flexible Li-S batteries. The resultant hybrid sulfur cathode with a tortuosity of 2.42 and a porosity of 0.44 delivers prominent rate performance and cycling stability with a medium sulfur loading. More importantly, we demonstrate that the pouch cells with a high sulfur loading of 6.0 mg cm-2 and a low electrolyte to sulfur ratio of 4.2 μL mg-1 could synchronously deliver high gravimetric/volumetric energy densities of 424.1 Wh kg-1 and 469.2 Wh L-1, as well as decent cycling behavior under arbitrary bending conditions, which provides a ponderable reference for future flexible and wearable electronic devices.

Lithium-sulfur (Li-S) batteries are hampered by the infamous shuttle effect and slow redox kinetics, resulting in rapid capacity decay. Herein, a bifunctional catalysis CoB/BN@rGO with integrated structure and synergy effect between adsorption and catalysis is proposed to solve the above problems. The integrated CoB and BN are simultaneously and uniformly introduced on the rGO substrate through a one-step calcination strategy, applied to modify the cathode side of PP separator. The transition metal borides can catalyze the conversion of lithium polysulfides (Li2Sn, n ≥ 4), whereas the bond of B-S is too weak to absorb LPS. Thus BN introduced can effectively restrict the diffusion of polysulfides via strong chemisorption with LiSnLi+ ⋯N, while the rGO substrate ensures smooth electron transfer for redox reaction. Therefore, through the integrated adsorption/catalysis, the shuttle effect is suppressed, the kinetics of redox reaction is enhanced, and the capacity decay is reduced. Using CoB/BN@rGO modified PP separator, the Li-S batteries with high initial capacity (1450 mAh g−1 at 0.35 mA cm−2) and long-cycle stability (700 cycles at 1.74 mA cm−2 with a decay rate of 0.032% per cycle) are achieved. This work provides a novel insight for the preparation of bifunctional catalysis with integrated structure for long-life Li-S batteries.

Light-driven micromotors with high spatial resolution are powerful tools for targeted drug delivery and biomedical diagnosis. To combine the function of biosensing, light-driven micromotors have been modified with fluorescence materials such as quantum dots or dyes. However, these fluorescence micromotors are generally driven and excited by ultraviolet or visible lights, which may cause photo-damage to biological cells or tissues. Here we propose upconversion fluorescence micromotors (UCFMs) constructed by lanthanide (NaYF

Efficient and long-term stable electrocatalysts for the hydrogen evolution reaction (HER) via water splitting are urgently desired to ease the energy crisis and develop the sustainability of human society. However, the HER performance of state-of-the-art Pt in non-acidic solutions is unsatisfactory due to the severely sluggish kinetics. Here, DFT theoretical calculations reveal that the Ru/RuO2 composites enable high HER activity to be pursued under non-acidic conditions because of the distinctive Ru and RuO2 interface, which possess not only a strong capability to adsorb and dissociate water but also appropriate binding energies of H and OH. Therefore, we employ a simple strategy, including heating under an oxygen-poor environment and/or in situ electrochemical reduction, to partially reduce RuO2. The formed Ru/RuO2 interfaces demonstrate superior HER activities (e.g. η10 = 17 mV, 35 mV dec−1 in 1 M KOH) than Pt/C (e.g. η10 = 27 mV, 58 mV dec−1 in 1 M KOH) at both small (10–100 mA cm−2) and large (1 A cm−2) current densities in alkaline solution and even real seawater. Comprehensive experiments were conducted to investigate the structure-HER performance relationships. Moreover, benefiting from the bifunctional character of RuO2, a two-electrode system based on Ru/RuO2 composites and RuO2 exhibits the lowest cell voltage for water splitting in both 1 M KOH and 0.5 M H2SO4, respectively. A 300 h-stability test at 10 mA cm−2 without an obvious decay demonstrates the industrial prospects of the Ru/RuO2 composites to generate green energy.

The construction of self-supporting and robust electrodes with high energy density and enduring redox chemistry is pivotal for developing high-performance lithium–sulfur (Li–S) batteries towards flexible electronics, whose practical applications are hampered by the shuttling of lithium polysulfide (LiPS) and sluggish reaction kinetics. 2D heterostructured materials integrating laminated morphology and stable compositions have attracted intensive interest for rapid ion/electron transfer, which are desperately needed in various energy storage applications. Herein, MXene-based flexible sulfur cathodes utilizing V2C/VO2 nanoribbon intertwined V2C/VO2 nanosheet (VCOR–VCOS) dual heterostructures as skeleton matrices are designed, in which the V2C/VO2 nanoribbon is in situ pillared between the adjacent V2C/VO2 layers during the hydrothermal process, providing a lightweight sandwich-type architecture with high mechanical robustness, unobstructed electron/Li+ ion transfer and catalytic properties for LiPS redox reactions. By virtue of these preponderances of VCOR–VCOS, pouch cells with an areal S loading of 6.0 mg cm−2 and an electrolyte to sulfur ratio of 4.5 μL mg−1 deliver a superior areal capacity of 6.3 mA h cm−2 and excellent capacity retention under arbitrary bending conditions, which provide a ponderable reference for future flexible electronic devices.

Potassium-ion batteries (PIBs) possess great potential in new-generation large-scale energy storage. However, their applications are plagued by large volume change and sluggish reaction kinetics of the electrode materials during the repeated charge/discharge processes. Guided by computerization modeling, we, herein, report the atomic-scale interfacial regulation of Sb

The gravimetric, areal, and volumetric capacities pose important influences on market penetration for secondary batteries. Carbonaceous materials take a leading stand for the improvement of gravime...

The cobalt triphosphide (CoP3) was grew on carbon paper (CP) by using a hydrothermal method and served as counter electrode (CE) catalyst in dye-sensitized solar cells (DSSCs). The morphology of the CoP3/CP CE exhibits a regular fibrous structure, which provides a guarantee for its good electrochemical performance of the CE made from the cyclic voltammetry, Tafel test, etc. Various photoelectric performance tests also show that the DSSCs with CoP3/CP CE achieves good photoelectric conversion efficiency of 6.84% under 100 mW·cm−2 illumination, which can compare to that of the DSSC assembled with the Pt (6.79%) CE. Metal phosphides are rarely used as CEs in DSSCs, and they will have a good promising alternative to the Pt electrode in the future.

Aluminum alloy AA2024 has superior characteristics, including high specific strength, excellent corrosion resistance, and remarkable mechanical properties. Moreover, it has an undeniable role in the aerospace and automotive industries, which originates from its lightweight. As an advanced sheet metal in the 3D printing technology, the incremental forming process also has unique advantages in the rapid and small batch production of components in aerospace and automotive industries. The present study investigates the mechanical characteristics of AA2024 sheets at different heat treatment conditions. Moreover, effects of different process parameters on the incremental forming limit are studied through tensile and warm incremental forming experiments. It is intended to provide a guideline for aluminum alloy AA2024 sheet forming. Obtained results from tensile strength experiments indicate that the elevated temperature can reduce the tensile strength of AA2024-T4 by 26.14% and increase its uniform elongation by 28.29%. Incremental forming experiments show that as the temperature increases, the forming angle limit of AA2024-T4 increases by 21.98%. However, it is still lower than the forming angle limit of AA2024-O by 18.38% at the room temperature. It is found that a variable-angle busbar shape, larger feed rate, and lower pitch value can make a component with a greater forming limit. Compared with the stamping process, the incremental forming process can significantly increase the forming limit of the AA2024 sheet, indicating that the incremental forming process is a good choice for AA2024 sheet forming.

The reasonable design of metal compound electrocatalysts is proved to be a good approach to accelerate the sluggish conversion kinetics of polysulfides for high performance lithium–sulfur (Li–S) batteries. Since metal cations usually serve as the active sites to interact with polysulfides, optimizing their electronic and valence states is vital to enhance catalytic activity, especially for electrochemical reactions involving multiple electrons. Herein, the electronic and valence states of metal active sites in hollow carbon-encapsulated Ni3ZnC0.7 (denoted as C/Ni3ZnC0.7) nanospheres are modulated by introducing either donor defects (P dopants) or acceptor defects (Ni vacancies) via P-doping or NaBH4-etching, respectively. Such P dopants and Ni vacancies not only endow P-doped C/Ni3ZnC0.7 (denoted as C/Ni3ZnC0.7-Pm) and NaBH4-etched C/Ni3ZnC0.7 (denoted as C/Ni3ZnC0.7-Bn) nanospheres with abundant defects and distortions, but also modulate the valence states of metal active sites in different ways. P dopants and accompanied Zn vacancies remarkably decrease the electron density of Zn active sites in C/Ni3ZnC0.7-P5 while the Ni vacancies contribute to the dramatic increase of Ni2+ species in C/Ni3ZnC0.7-B1 nanospheres. The modulated Zn sites could anchor polysulfides and serve as reservoirs to regulate the valence of Ni sites. However, the modulated Ni active sites with more Ni2+ species enable fast electron transfer between the Ni2+/Ni(0) pair and polysulfides, playing a more significant role in catalyzing the conversion of polysulfides. As a result, compared with C/Ni3ZnC0.7 and C/Ni3ZnC0.7-P5, C/Ni3ZnC0.7-B1 with more Ni2+ species exhibits stronger chemical adsorption ability toward polysulfides and catalytic ability to accelerate the conversion kinetics of polysulfides. When C/Ni3ZnC0.7-B1 nanospheres are used to modify commonly used PP separators for Li–S batteries, remarkable rate performance up to 4.0C (525.6 mA h g−1) and excellent cycling stability (a decay of 0.0179% over 1400 cycles at 1.0C) are achieved.

Bone marrow mesenchymal stem cells (BMSCs) hold a high osteogenic differentiation potential, but the mechanisms that control the osteogenic ability of BMSCs from osteoporosis (OP-BMSCs) need further research. The purpose of this experiment is to discuss the osteogenic effect of Mettl3 on OP-BMSCs and explore new therapeutic target that can enhance the bone formation ability of OP-BMSCs.The bilateral ovariectomy (OVX) method was used to establish the SD rat OP model. Dot blots were used to reveal the different methylation levels of BMSCs and OP-BMSCs. Lentiviral-mediated overexpression of Mettl3 was applied in OP-BMSCs. QPCR and WB detected the molecular changes of osteogenic-related factors and Wnt signalling pathway in vitro experiment. The staining of calcium nodules and alkaline phosphatase detected the osteogenic ability of OP-BMSCs. Micro-CT and histological examination evaluated the osteogenesis of Mettl3 in OP rats in vivo.The OP rat model was successfully established by OVX. Methylation levels and osteogenic potential of OP-BMSCs were decreased in OP-BMSCs. In vitro experiment, overexpression of Mettl3 could upregulate the osteogenic-related factors and activate the Wnt signalling pathway in OP-BMSCs. However, osteogenesis of OP-BMSCs was weakened by treatment with the canonical Wnt inhibitor Dickkopf-1. Micro-CT showed that the Mettl3(+) group had an increased amount of new bone formation at 8 weeks. Moreover, the results of histological staining were the same as the micro-CT results.Taken together, the methylation levels and osteogenic potential of OP-BMSCs were decreased in OP-BMSCs. In vitro and in vivo studies, overexpression of Mettl3 could partially rescue the decreased bone formation ability of OP-BMSCs by the canonical Wnt signalling pathway. Therefore, Mettl3 may be a key targeted gene for bone generation and therapy of bone defects in OP patients.

We demonstrate that red blood cells (RBCs), with an adjustable focusing effect controlled by optical forces, can act as bio-microlenses for trapping and imaging subwavelength objects. By varying the laser power injected into a tapered fiber probe, the shape of a swelled RBC can be changed from spherical to ellipsoidal by the optical forces, thus adjusting the focal length of such bio-microlens in a range from 3.3 to 6.5 µm. An efficient optical trapping and a simultaneous fluorescence detecting of a 500-nm polystyrene particle have been realized using the RBC microlens. Assisted by the RBC microlens, a subwavelength imaging has also been achieved, with a magnification adjustable from 1.6× to 2×. The RBC bio-microlenses may offer new opportunities for the development of fully biocompatible light-driven devices in diagnosis of blood disease.

The Gibberellic Acid Stimulated Arabidopsis (GASA) proteins were investigated in the study to help understand their possible roles in fruit trees, particularly in Citrus. A total of 18 CcGASA proteins were identified and characterized in Citrus clementina via a genome-wide approach. It was shown that the CcGASA proteins structurally shared a conserved GASA domain but varied considerably in primary sequences and motif compositions. Thus, they could be classified into three major phylogenetic groups, G1~G3, and two groups, G1 and G3 could be further classified into subgroups. The cis- elements on all CcGASA promoters were identified and categorized, and the associated transcription factors were predicted. In addition, the possible interactions between the CcGASA proteins and other proteins were predicted. All the clues suggested that these genes should be involved in defense against biotic and abiotic stresses and in growth and development. The notion was further supported by gene expression analysis that showed these genes were more or less responsive to the treatments of plant hormones (GA3, SA, ABA and IAA), and infections of citrus canker pathogen Xanthomonas citri. It was noted that both the segmental and the tandem duplications had played a role in the expansion of the CcGASA gene family in Citrus. Our results showed that the members of the CcGASA gene family should have structurally and functionally diverged to different degrees, and hence, the representative group members should be individually investigated to dissect their specific roles.

Hydrogen evolution reaction (HER) is one of the key components for the hydrogen-centered renewable clean energy system. Developing efficient HER electrocatalysts that make use of earth-abundant elements is highly desirable yet challenging. Herein, we report a three-dimensional (3-D) CoP3 nanoplate arrays in situ grown on carbon cloth (CoP3 NPAs/CC), which is synthesized by a facile topotactic phosphidation method under hydrothermal condition. As a HER electrocatalyst, the as-prepared CoP3 NPAs/CC exhibit great catalytic activity that is comparable to Pt, over a large pH range of 0–14. At pH = 0, such flexible and efficient CoP3 electrocatalysts can deliver a high current density of 100 mA cm−2 at an overpotential as low as 113 mV, with no apparent activity loss over 40 h. By theoretical calculation and experimental measurements, the outstanding HER performance of the CoP3 NPAs/CC can be attributed to the good conductivity property, synergistic effect between Co and P, unique rich-phosphorous CoP3 nanoplate arrays structure and the great intrinsic catalytic activity. As a highly efficient HER catalyst, CoP3 NPA offers a promising alternative of non-PGM catalysts for electrochemical hydrogen production.

Moderate anionic doping is an effective approach to improve the performance of electrocatalysts toward hydrogen evolution reaction (HER) since it can adjust the electronic structure, active site, and phase. The reported studies mainly focus on designing P doped CoS2, while other phases of cobalt sulfide, such as Co1−xS and Co9S8 doped with P are rarely investigated for HER electrocatalysts. Herein, various cobalt sulfides (including CoS2/Co1−xS, Co1−xS, and Co9S8) doped with P are anchored on carbon cloth through a facile hydrothermal method. Among tested electrocatalysts, P doped Co1−xS exhibits excellent electrocatalytic performance with an overpotential of 110 and 165 mV (vs. RHE) for current densities of 10 and 100 mA·cm−2, respectively. Density functional theory calculations reveal that P doped Co1−xS possesses a smaller bandgap and more optimal hydrogen adsorption sites than pristine Co1−xS. This work initially investigates various cobalt sulfides doped with P and further gets insight into the activity improvement mechanism of P doping, which could guide the design of earth-abundant HER electrocatalysts for the “hydrogen economy”.

The radial geometry with rays radiated from a common core occurs ubiquitously in nature for its symmetry and functions. Herein, we report a class of synthetic asters with well-defined core-ray geometry that can function as elastic and radial skeletons to harbor nano- and microparticles. We fabricate the asters in a single, facile, and high-yield step that can be readily scaled up; specifically, amphiphilic gemini molecules self-assemble in water into asters with an amorphous core and divergently growing, twisted crystalline ribbons. The asters can spontaneously position microparticles in the cores, along the radial ribbons, or by the outer rims depending on particle sizes and surface chemistry. Their mechanical properties are determined on single- and multiple-aster levels. We further maneuver the synthetic asters as building blocks to form higher-order structures in virtue of aster-aster adhesion induced by ribbon intertwining. We envision the astral structures to act as rudimentary spatial organizers in nanoscience for coordinated multicomponent systems, possibly leading to emergent, synergistic functions., Nanosystems capable of organisation and the formation of structures are of interest in nanotechnology. Here, the authors report on synthetic asters made of gemini surfactant which are able to position microparticles based on size and chemical composition which can also be organised into higher order structures.

Pursuing cost-effective water-splitting catalysts is still a significant scientific challenge to produce renewable fuels and chemicals from various renewable feedstocks. The construction of controllable binder-free nanostructures with self-standing holey and ultrathin nanosheets is one of the promising approaches. Herein, by employing a combination of the potentiodynamic mode of electrodeposition and low-temperature phosphidation, three-dimensional (3D) holey CoP ultrathin nanosheets are fabricated on a carbon cloth (PD-CoP UNSs/CC) as bifunctional catalysts. Electrochemical tests show that the PD-CoP UNSs/CC exhibits outstanding hydrogen evolution reaction performance at all pH values with overpotentials of 47, 90, and 51 mV to approach 10 mA cm-2 in acidic, neutral, and alkaline media, respectively. Meanwhile, only a low overpotential of 268 mV is required to drive 20 mA cm-2 for the oxygen evolution reaction in alkaline media. Cyclic voltammetry and impedance studies suggest the enhanced performance is mainly attributed to the unique 3D holey ultrathin nanosheets, which could increase the electrochemically active area, facilitate the release of gas bubbles from electrode surfaces, and improve effective electrolyte diffusion. This work suggests an efficient path to design and fabricate non-noble bifunctional electrocatalysts for water splitting at a large scale.

Highly efficient and low-cost electrocatalysts toward oxygen evolution reaction (OER) hold their promises in renewable energy technologies such as water splitting. Herein, we reported a fast electrodeposition of highly efficient NiFe alloy onto three-dimension nickel foam (NF). Benefiting from the hierarchical structure, NiFe/NF exhibits high OER efficiency with a low onset potential and a low overpotential (191 mV at 10 mA cm−2), which outperforms the commercial catalyst and most reported catalysts up-to-date. Also, it shows a remarkably low Tafel slope of 44.1 mV as well as a long-time stability that the potential increased less than 10 mV after 30000 s OER at 100 mA cm−2. NiFe/NF is expected to surpass the commercial catalyst to serve as a non-noble-metal-based electrocatalyst for OER practical application.

To address the challenge of highly efficient water splitting into H2, successful fabrication of novel porous three-dimensional Ni-doped CoP3 nanowall arrays on carbon cloth was realized, resulting in an effective self-supported electrode for the electrocatalytic hydrogen-evolution reaction. The synthesized samples exhibit rough, curly, and porous structures, which are beneficial for gaseous transfer and diffusion during the electrocatalytic process. As expected, the obtained Ni-doped CoP3 nanowall arrays with a doping concentration of 7% exhibit the promoted electrocatalytic activity. The achieved overpotentials of 176 mV for the hydrogen-evolution reaction afford a current density of 100 mA cm−2, which indicates that electrocatalytic performance can be dramatically enhanced via Ni doping. The Ni-doped CoP3 electrocatalysts with increasing catalytic activity should have significant potential in the field of water splitting into H2. This study also opens an avenue for further enhancement of electrocatalytic performance through tuning of electronic structure and d-band center by doping.

Objective: Although it has been demonstrated that adipose-derived stem cells (ASCs) from osteoporosis mice (OP-ASCs) exhibit impaired osteogenic differentiation potential, the molecular mechanism has not yet been elucidated. We found that Fzd6 was decreased in OP-ASCs compared with ASCs. This study investigates the effects and underlying mechanisms of Fzd6 in the osteogenic potential of OP-ASCs. Methods: Fzd6 expression in ASCs and OP-ASCs was measured by PCR gene chip. Fzd6 overexpression and silencing lentiviruses were used to evaluate the role of Fzd6 in the osteogenic differentiation of OP-ASCs. Real-time PCR (qPCR) and western blotting (WB) was performed to detect the expression of Fzd6 and bone-related molecules, including runt-related transcription factor 2 (Runx2) and osteopontin (Opn). Alizarin red staining and Alkaline phosphatase (ALP) staining was performed following osteogenic induction. Microscopic CT (Micro-CT), hematoxylin and eosin staining (H&E) staining, and Masson staining were used to assess the role of Fzd6 in osteogenic differentiation of osteoporosis (OP) mice in vivo.Results: Expression of Fzd6 was decreased significantly in OP-ASCs. Fzd6 silencing down-regulated the osteogenic ability of OP-ASCs in vitro. Overexpression of Fzd6 rescued the impaired osteogenic capacity in OP-ASCs in vitro. We obtained similar results in vivo.Conclusions: Fzd6 plays an important role in regulating the osteogenic ability of OP-ASCs both in vivo and in vitro. Overexpression of Fzd6 associated with the Wnt signaling pathway promotes the osteogenic ability of OP-ASCs, which provides new insights for the prevention and treatment of OP.

The cobalt oxides and manganese oxides have high-activity potential for catalytic oxidation of volatile organic compounds (VOCs), while the mesoporous hollow morphology is crucial to the mass transfer of reactant and product. Therefore, it is worth investigating the effect of manganese substitution in mesoporous hollow cobalt oxides on catalytic oxidation. Herein, a partially disordered spinel structure is formed by the Mn substitution in Co3O4 and the mesoporous hollow microsphere is improved in morphology homogeneity with the decrease of Co/Mn ratio in the range of 1.8–28.8. The 5Co1Mn (Mn-substituted Co3O4 with Co/Mn at 5.4) exhibits outstanding catalytic activity for toluene oxidation with 50% CO2 generation at 237 °C, which is 21 °C lower than Co3O4. Moreover, the 5Co1Mn displays satisfactory stability in reusability, lifetime, and water resistance. The small defective crystallite, mesoporous hollow morphology, and high specific surface area endow Mn-substituted Co3O4 with more surface chemical adsorbed oxygen, enhancing the catalytic oxidation of toluene. Theoretical calculation on (3 1 1) plane of Co3O4 reveals that Mn2+ or Mn3+ substitution increases the formation energy of oxygen vacancy and makes it difficult to adsorb gaseous oxygen on the defective surface. The interaction between Co and Mn impedes the improvement of toluene oxidation because the mobility of lattice oxygen, the surface distribution of Co3+, and the ratio of surface adsorbed oxygen to surface lattice oxygen are hindered by Mn substitution. The chemical adsorbed oxygen is more active than lattice oxygen in the oxidation of adsorbed intermediates (phenolate, benzoate species, etc.). The Langmuir-Hinshelwood mechanism dominates in the catalytic oxidation at 200–250 °C, while the catalytic oxidation follows both the Langmuir-Hinshelwood mechanism and Mars-van Krevelen mechanism above 250 °C. This work provides some enlightenment for exploring the role of surface oxygen species in VOCs oxidation and uncovering the interaction in binary spinel oxides.

Noninvasive and sensitive thermometry of a single living cell is crucial to the analysis of fundamental cellular processes and applications to cancer diagnosis. Optical fibers decorated with temperature-sensitive nanomaterials have become widely used instruments for biosensing temperature. However, current silica fibers exhibit low compatibility and degradability in biosystems. In this work, we employ spider silks as natural optical fibers to construct biocompatible thermometers. The spider silks were drawn directly from Araneus ventricosus and were decorated with core-shell upconversion nanoparticles (UCNPs) via a photophoretic effect. By measuring the fluorescence spectra of the UCNPs on the spider silks, the membrane temperature of a single breast cancer cell was obtained with absolute and relative sensitivities ranging from 3.3 to 4.5 × 10-3 K-1 and 0.2 to 0.8% K-1, respectively. Additionally, the temperature variation during apoptosis was monitored by the thermometer in real time. This work provides a biocompatible tool for precise biosensing and single-cell analysis.