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Photocatalysis technology based on solar-powered semiconductors is widely recognized as a promising approach for achieving eco-friendly, secure, and sustainable degradation of organic contaminants. Nevertheless, conventional photocatalysts exhibit drawbacks such as a wide bandgap, and rapid recombination of photoinduced electron/hole pairs, in addition to complicated separation and recovery procedures. In this research, we cultivated BiOBr in situ on the surface of copper foam to fabricate a functional photocatalyst (denoted as BiOBr/Cu foam), which was subsequently employed for the photodegradation of Methylene Blue. Based on photodegradation experiments, the 0.3 BiOBr/Cu foam demonstrates superior photocatalytic efficacy compared to other photocatalysts under solar light irradiation. Furthermore, its ease of separation from the solution enhances its potential for reuse. The analysis of charge transfer revealed that the copper foam functions as an effective electron scavenger within the BiOBr/Cu foam, thereby facilitating charge separation and the generation of photo-induced holes. This phenomenon contributes to a significantly enhanced production of hydroxyl radicals. This study provides a valuable perspective on the design and synthesis of photocatalysts with heightened practicality, employing a conductive substrate.

Water droplets containing the SARS-CoV-2 virus, responsible for coronavirus 2019 transmission, were introduced into a controlled-temperature and -humidity chamber. The SARS-CoV-2 virus with green fluorescent protein tag in droplets was used to infect Caco-2 cells, with viability assessed through flow cytometry and microscopic counting. Whereas temperature fluctuations within typical indoor ranges (20°C–30°C) had minimal impact, we observed a notable decrease in infection rate as the surrounding air’s relative humidity increased. By investigating humidity levels between 20% and 70%, we identified a threshold of ≥40% relative humidity as most effective in diminishing SARS-CoV-2 infectivity. We also found that damage of the viral proteins under high relative humidity may be responsible for the decrease in their activity. This outcome supports previous research demonstrating a rise in the concentration of reactive oxygen species within water droplets with elevated relative humidity.

Abstract Autonomous exploration is a critical technology to realize robotic intelligence as it allows unsupervised preparation for future tasks and facilitates flexible deployment. In this paper, a novel Deep Reinforcement Learning (DRL) based autonomous exploration strategy is proposed to efficiently reduce the unknown area of the workspace and provide accurate 2D map construction for mobile robots. Different from existing human-designed exploration techniques that usually make strong assumptions about the scenarios and the tasks, we utilize a model-free method to directly learn an exploration strategy through trial-and-error interactions with complex environments. To be specific, the Generalized Voronoi Diagram (GVD) is first utilized for domain conversion to obtain a high-dimensional Topological Environmental Representation (TER). Then, the Generalized Voronoi Networks (GVN) with spatial awareness and episodic memory is designed to learn autonomous exploration policies interactively online. For complete and efficient exploration, Invalid Action Masking (IAM) is employed to reshape the configuration space of exploration tasks to cope with the explosion of action space and observation space caused by the expansion of the exploration range. Furthermore, a well-designed reward function is leveraged to guide the learning of policies. Extensive baseline tests and comparative simulations show that our strategy outperforms the state-of-the-art strategies in terms of map quality and exploration speed. Sufficient ablation studies and mobile robot experiments demonstrate the effectiveness and superiority of our strategy.

Abstract One‐step deposition approaches have been widely applied and developed in the fabrication of quasi‐2D perovskites. However, the regulation of quantum wells (QWs) and crystalline orientation is difficult and complicated when using this methodology. Sequential deposition is another widespread synthetic approach for preparing perovskite films and perovskite dimension engineering. In this article, δ‐CsPbI3 intermediate phase assisted sequential (IPAS) deposition is successfully carried out to fabricate MA‐free quasi‐2D ACI perovskites. The amount of the δ‐CsPbI3 intermediate phase in the PbI2 layer and the concentration of GAI molecule in the IPA solution both play important roles in the production of MA‐free quasi‐2D ACI perovskite films. The n value of the MA‐free quasi‐2D ACI perovskites can be adjusted, which affects the photovoltaic performance and device stability. Compared with one‐step deposition, the MA‐free quasi‐2D ACI perovskites prepared via IPAS deposition have opposite reverse‐graded QW distribution and improved vertical orientation, leading to a remarkable PEC of up to 18.86% and allowing the preparation of unpackaged devices with prominent working stability (80%, ~400 h). The underlying mechanism and crystallization pathway of IPAS deposition confirm that sequential deposition has unique superiority in regulating the QW distribution and crystalline orientation of quasi‐2D perovskites.

When plants encounter external environmental stimuli, they can adapt to environmental changes through a complex network of metabolism–gene expression–metabolism within the plant cell. In this process, changes in the characteristics of plant cells are a phenotype that is responsive and directly linked to this network. Accurate identification of large numbers of plant cells and quantitative analysis of their cellular characteristics is a much-needed experiment for in-depth analysis of plant metabolism and gene expression. This study aimed to develop an automated, accurate, high-throughput quantitative analysis method, ACFVA, for single-plant-cell identification. ACFVA can quantitatively address a variety of biological questions for a large number of plant cells automatically, including standard assays (for example, cell localization, count, and size) and complex morphological assays (for example, different fluorescence in cells). Using ACFVA, phenomics studies can be carried out at the plant cellular level and then combined with ever-changing sequencing technologies to address plant molecular biology and synthetic biology from another direction.

We synthesized ammonia (NH3) by bubbling nitrogen (N2) gas into bulk liquid water (200 mL) containing 50 mg polytetrafluoroethylene (PTFE) particles (~5 µm in diameter) suspended with the help of a surfactant (Tween 20, ~0.05 vol.%) at room temperature (25 °C). Electron spin resonance spectroscopy and density functional theory calculations reveal that water acts as the proton donor for the reduction of N2. Moreover, isotopic labeling of the N2 gas shows that it is the source of nitrogen in the ammonia. We propose a mechanism for ammonia generation based on the activation of N2 caused by electron transfer and reduction processes driven by contact electrification. We optimized the pH of the PTFE suspension at 6.5 to 7.0 and employed ultrasonic mixing. We found an ammonia production rate of ~420 µmol L-1h-1 per gram of PTFE particles for the conditions described above. This rate did not change more than 10% over an 8-h period of sustained reaction. [ABSTRACT FROM AUTHOR]

The La-based perovskite (LaBO3) exhibits excellent optical properties. However, its valence band (VB) potential is not sufficiently positive to reach the oxidation potential required for the cleavage of chemical bonds (such as benzylic C-H), limiting its application in photocatalysis. Herein, we report the unconventional effects of heat activation on the reduction of the dissociation energy of benzylic C-H and aqueous H-O, thereby triggering the photocatalytic activity of La2CoxMn2-xO6 perovskites. Additionally, we demonstrate that photocatalysis is the main contributor to substrate conversion in the selective oxidation of toluene and reduction of CO2. Particularly, La2Co1.5Mn0.5O6 shows excellent performance with a product yield of 550.00 mmol gcat-1 and a toluene conversion of 22,866.67 µmol gcat-1 h-1. To the best of our knowledge, this is the highest reported product yield for the selective oxidation of benzylic C-H bond of toluene. Our findings provide insight into the specific role of heat activation in photocatalysis, which is crucial for breaking and overcoming the VB barrier to realize challenging reactions. [ABSTRACT FROM AUTHOR]

Spontaneous generation of reactive oxygen species (ROS) in aqueous microdroplets or at a water vapor–silicate interface is a new source of redox chemistry. However, such generation occurs with difficulty in liquid water having a large ionic strength. We report that ROS is spontaneously produced when water vapor contacts hydrogen-bonded hydroxyl groups on a silicate surface. The evolution of hydrogen-bonded species such as hydroxyl groups was investigated by using two-dimensional, time-resolved FT-IR spectroscopy. The participation of water vapor in ROS generation is confirmed by investigating the reaction of D2O vapor and hydroxyl groups on a silicate surface. We propose a reaction pathway for ROS generation based on the change of the hydrogen-bonding network and corresponding electron transfer onto the silicate surface in the water vapor–solid contact process. Our observations suggest that ROS production from water vapor–silicate contact electrification could have contributed to oxidation during the Archean Eon before the Great Oxidation Event. [ABSTRACT FROM AUTHOR]

Contact electrification between water and a solid surface is crucial for physicochemical processes at water-solid interfaces. However, the nature of the involved processes remains poorly understood, especially in the initial stage of the interface formation. Here we report that H2O2 is spontaneously produced from the hydroxyl groups on the solid surface when contact occurred. The density of hydroxyl groups affects the H2O2 yield. The participation of hydroxyl groups in H2O2 generation is confirmed by mass spectrometric detection of 18O in the product of the reaction between 4-carboxyphenylboronic acid and 18O-labeled H2O2 resulting from 18O2 plasma treatment of the surface. We propose a model for H2O2 generation based on recombination of the hydroxyl radicals produced from the surface hydroxyl groups in the water-solid contact process. Our observations show that the spontaneous generation of H2O2 is universal on the surfaces of soil and atmospheric fine particles in a humid environment. [ABSTRACT FROM AUTHOR]

Magnetron sputtering is used for the fabrication of platinum/titanium bilayer counterelectrodes and the effect of thickness of both platinum and titanium layers on their structural, electrical and electrochemical properties is examined. The studies have shown that the as-prepared titanium layer is almost amorphous and intermetallic phase is formed between platinum and titanium layers.

A study was carried to examine the effect of lithium iodide concentration on the conduction behavior of poly(ethylene oxide)-poly(vinylidene fluoride) (PEO-PVDF) polymer-blend electrolyte and the corresponding performance of the dye-sensitized solar cell (DSSC). The results showed that the changes of conduction behavior and the changes of [I.sub.3.sup.-} and [I.sup.-] concentrations in the electrolytes influenced the final performance variation of the corresponding DSSC with varying LiI concentration.

The end-functional silicone coupling agent (dodecyl-trimethoxysilane, DTMS for short) was used to modify the PEO/P(VDF-HFP)/SiO2 nanocomposite polymer electrolyte (CPE) and the different amounts of DTMS modification effects were studied. The experiments showed the silicone coupling agent with hydrophobic alkyl chains (-C12H25) chemically engineered on the SiO2 nanoparticles, and formed a Si-O-Si cross-linked network in the new nanocomposite polymer electrolyte. Proper content of DTMS modified CPE exhibited improved ionic conductivity and the connection with the photoanode and counter electrode. However, much higher content of the DTMS modification changed the conformation of the polymer network and reduced the ionic movement. Compared with the performance (3.84%) of the original DSSC, the DSSC with functional silicone coupling agent modified CPE (DTMS:SiO2 = 2:1, mol ratio) exhibited improved Jsc (7.94 mA cm[?]2), Voc (0.624 V) and optimal efficiency (5.2%) (measured at AM1.5, light intensity of 58.4 mW cm[?]2). The Voc of the silicone coupling agent modified polymer electrolyte DSSC is obviously improved, which is mainly due to that the hydrophobic alkyl chain end groups formed an insulating layer that retarded the electron recombination at the TiO2 nanoporous photoanode/polymer electrolyte interface. The DTMS:SiO2 = 2:1 modified CPE type DSSC exhibited a performance of 6.42% at a light intensity of 32.1 mW cm[?]2 and 4.94% at 99.2 mW cm[?]2. [ABSTRACT FROM AUTHOR]

A surface modification method was carried out by reactive DC magnetron sputtering to fabricate TiO2 electrodes coated with insulating MgO for dye-sensitized solar cells. The MgO-coated TiO2 electrode had been characterized by x-ray photoelectron spectroscopy (XPS), energy-dispersive x-ray spectroscopy (EDX), scanning electron microscopy (SEM), UV-vis spectrophotometer, cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The study results revealed that the TiO2 modification increases dye adsorption, decreases trap states and suppresses interfacial recombination. The effects of sputtering MgO for different times on the performance of DSSCs were investigated. It indicated that sputtering MgO for 3 min on TiO2 increases all cell parameters, resulting in increasing efficiency from 6.45% to 7.57%. [ABSTRACT FROM AUTHOR]