Wearable electrochemical biosensors for sweat analysis present a promising means for noninvasive biomarker monitoring. However, sweat‐based sensing still poses several challenges, including easy degradation of enzymes and biomaterials with repeated testing, limited detection range and sensitivity of enzyme‐based biosensors caused by oxygen deficiency in sweat, and poor shelf life of sensors using all‐in‐one working electrodes patterned by traditional techniques (e.g., electrodeposition and screen printing). Herein, a stretchable, wearable, and modular multifunctional biosensor is developed, incorporating a novel MXene/Prussian blue (Ti3C2Tx/PB) composite designed for durable and sensitive detection of biomarkers (e.g., glucose and lactate) in sweat. A unique modular design enables a simple exchange of the specific sensing electrode to target the desired analytes. Furthermore, an implemented solid–liquid–air three‐phase interface design leads to superior sensor performance and stability. Typical electrochemical sensitivities of 35.3 µA mm−1 cm−2 for glucose and 11.4 µA mm−1 cm−2 for lactate are achieved using artificial sweat. During in vitro perspiration monitoring of human subjects, the physiochemistry signals (glucose and lactate level) can be measured simultaneously with high sensitivity and good repeatability. This approach represents an important step toward the realization of ultrasensitive enzymatic wearable biosensors for personalized health monitoring.

The application of graphite anodes in potassium-ion batteries (KIB) is limited by the large variation in lattice volume and the low diffusion coefficient of potassium ions during (de)potassiation. This study demonstrates nitrogendoped, defect-rich graphitic nanocarbons (GNCs) as high-performance KIB anodes. The GNCs with controllable defect densities are synthesized by annealing an ethylenediaminetetraacetic acid nickel coordination compound. The GNCs show better performance than the previously reported thin-walled graphitic carbonaceous materials such as carbon nanocages and nanotubes. In particular, the GNC prepared at 600 °C shows a stabilized capacity of 280 mAh g −1 at 50 mA g −1 , robust rate capability, and long cycling life due to its high-nitrogen-doping, short-range-ordered, defect-rich graphitic structure. A high capacity of 189 mAh g −1 with a long cycle life over 200 cycles is demonstrated at a current density of 200 mA g −1 . Further, it is confirmed that the potassium ion storage mechanism of GNCs is different from that of graphite using multiple characterization methods. Specifically, the GNCs with numerous defects provide more active sites for the potassiation process, which results in a final discharge product with short-range order. This study opens a new pathway for designing graphitic carbonaceous materials for KIB anodes.

Solar desalination driven by solar radiation as heat source is freely available, however, hindered by low efficiency. Herein, we first design and synthesize black titania with a unique nanocage structure simultaneously with light trapping effect to enhance light harvesting, well-crystallized interconnected nanograins to accelerate the heat transfer from titania to water and with opening mesopores (4-10 nm) to facilitate the permeation of water vapor. Furthermore, the coated self-floating black titania nanocages film localizes the temperature increase at the water-air interface rather than uniformly heating the bulk of the water, which ultimately results in a solar-thermal conversion efficiency as high as 70.9% under a simulated solar light with an intensity of 1 kW m (1 sun). This finding should inspire new black materials with rationally designed structure for superior solar desalination performance.

Self-assembly allows structures to organize themselves into regular patterns by using local forces to find the lowest-energy configuration. However, assembling organic and inorganic building blocks in an ordered framework remains challenging due to  difficulties in rationally interfacing two dissimilar materials. Herein, the ensemble of polyoxometalates (POMs) and cyclodextrins (CDs) as molecular building blocks (MBBs) has yielded two unprecedented POM-CD-MOFs, namely [PW12O40]3– and α-CD MOF (POT-CD) as well as [P10Pd15.5O50]19– and γ-CD MOF (POP-CD), with distinct properties not shared by their isolated parent MBBs. Markedly, the POT-CD features a nontraditional enhanced Li storage behavior by virtue of a unique “amorphization and pulverization” process. This opens the door to a new generation of hybrid materials with tuned structures and customized functionalities.

Laser scribing of porous graphene electrodes on flexible substrates is of great interest for developing disposable electrochemical biosensors. In this work, we present a new patterning process for highly conductive nitrogen-doped graphene derived from a lignin-based precursor. A CO2 laser scribing process was performed under ambient conditions to produce the porous graphene electrodes from lignin. The obtained nitrogendoped laser-scribed graphene (N-LSG) is binder-free, hierarchical, and conductive. The interconnected carbon network displayed enhanced electrochemical activity with improved heterogeneous electron transfer rate. These features can be attributed to the highconductivity of porous N-LSG (down to 2.8 Ω per square) and its enriched active edge plane sites. Furthermore, the N-LSG electrodes were decorated with MXene/Prussian Blue (Ti3C2Tx/PB) composite via a simple spray coating process, designed for sensitive

Black titania, with greatly improved solar absorption, has demonstrated its effectiveness in photocatalysis and photoelectrochemical cells (PEC), inspiring us to explore the blackening of other wide band-gap oxide materials for enhanced performance. Herein, we report the fabrication of black, reduced Nb2O5 nanorods (r-Nb2O5), with active exposed (001) surfaces, and their enhanced photocatalytic and PEC properties. Black r-Nb2O5 nanorods were obtained via reduction of pristine Nb2O5 by molten aluminum in a two-zone furnace. Unlike the black titania, r-Nb2O5 nanorods are well-crystallized, without a core-shell structure, which makes them outstanding in photocatalytic stability. Substantial Nb(4+) cation and oxygen vacancies (VO) were introduced into r-Nb2O5, resulting in the enhanced absorption in both the visible and near-infrared regions and improved charge separation and transport capability. The advantage of the r-Nb2O5 was also proved by its more efficient photoelectrochemical performance (138 times at 1.23 VRHE) and higher photocatalytic hydrogen-generation activity (13 times) than pristine Nb2O5. These results indicate that black r-Nb2O5 is a promising material for PEC application and photocatalysis.

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Insulin inhibits transcription factor Forkhead box O (FoxO) activity, and the steroid hormone 20-hydroxyecdysone (20E) activates FoxO; however, the mechanism is unclear. We hypothesized that 20E upregulates phosphatidylinositol-3,4,5-trisphosphate 3-phosphatase (PTEN) expression to activate FoxO, thereby promoting proteolysis during molting in the lepidopteran insect Helicoverpa armigera. FoxO expression is increased during molting and metamorphosis.