Two-dimensional materials show great potential for future optoelectronic device applications, especially in the field of broadband optical detection, due to their high optical responsivity and tunable bandgap structure. In communication and sensing applications, the detection of weak light signals is crucial for improving the quality of signal transmission and the sensitivity of sensors. Although the photogating effect has been shown to provide high light sensitivity, the key features to achieve this dominant light response have not been fully discussed. In this study, we explain in detail the physical mechanism of the photoresponse of molybdenum disulphide-based photodetectors and propose a general basis of judgement for comparing the magnitude of the trap-state action. Through experimental and theoretical analyses, we reveal the physical mechanisms of photocurrents at various stages in the optical ON/OFF switching cycles and provide a theoretical basis for optimising the performance of two-dimensional material-based photodetectors. The results show that the trap states significantly affect the photoresponse characteristics of photodetectors, especially the photocurrent changes at different stages of the optical ON/OFF switching cycles. These findings not only deepen the understanding of the photoelectric properties of two-dimensional materials, but also provide important theoretical guidance for the design of high-performance photodetectors.

Nitrogenase enzymes catalyze the reduction of N to NH at a complex Fe-M (M = Mo, Fe, or V) cofactor (FeMco), which displays eight metal centers and sulfide and carbide bridges with a MFeSC composition. The role of the unusual μ-carbide ligand and its effects on the metal centers remain unclear. Here, we describe the transfer of a carbide ligand to a MoFeS cluster supported by a bisphenoxide ligand from a previously reported terminal Mo carbide complex to yield a pentametallic cluster of MoSFeCMo composition, which also displays a bridging CO that resembles the form of nitrogenase. This cluster has an = 1/2 spin state amenable to studies by pulse EPR spectroscopy, revealing a significantly larger carbide C hyperfine interaction ((C) = 12.5 MHz) than any observed for various states of FeMoco studied by EPR thus far (|(C)| = 0.89 to 2.7 MHz). This report provides a strategy for the synthesis of carbide-containing iron-sulfur clusters relevant to nitrogenase cluster modeling, as well as benchmarking information for the metal-carbon interactions by EPR methods.

Molybdenum dialkyldithiocarbamate is a highly effective friction modifier lubricant additive in boundary lubrication, owing to the formation of a MoS nanosheet lattice structure that significantly reduces friction. The friction reduction behaviour is linked to the MoS amount and coverage buildup at the contacting interface, however, accurately predicting friction reduction based on a semi-deterministic model incorporating MoS formation and removal remains challenging. In this study, a Raman map collection methodology was developed for accurate quantitative analysis of MoS tribofilms. The growth rate of MoS tribofilms was determined by coupling tribochemical experimental data with sophisticated numerical models. A full numerical procedure was implemented under rubbing of two rough surfaces at different temperatures. The results demonstrated localised MoS tribofilms buildup. The friction coefficients show a close agreement with the measurements. The developed model can be adapted to diverse experimental setups and surface geometries.

Although the nanosheet of molybdenum(IV) disulfide (MoS) has been widely recognized as a high-performance green nanoadditive for friction reduction and wear resistance, its low isolated yield and poor colloidal stability in lubricating base oils have become bottlenecks for practical tribological applications. In this work, we report the synthesis of α-lipoate functionalized triblock copolymers and their utilization in directly dispersing bulky MoS as a form of oleogels. The resulting polymer-inorganic composite oleogels are characterized by microscopic imaging, small-angle X-ray scattering, and rheology, demonstrating that the bulky MoS is exfoliated in situ into nanosheets driven by multiple Mo-S coordinating bonds. Notably, this process does not require preexfoliation or separate synthesis of MoS nanosheets. The polymer-nanosheet networks exhibit long-term dispersible and colloidal stability in base oils and excellent lubricating properties. Furthermore, the degree of MoS exfoliation increases with the degree of polymerization of the α-lipoate-containing blocks, resulting in enhanced lubricating performance of composite oleogels. The improved lubricity is attributed to a thicker protective tribofilm enriched with MoS nanosheets formed on the rubbing surface. More importantly, the direct use of bulk MoS as a lubricant additive with the assistance of α-lipoate-containing triblock copolymers establishes a facile strategy for the design of highly efficient green lubricants.

Dental caries is a localized deterioration of hard tissues caused by acidic by-products of bacterial fermentation of dietary carbohydrates. However, except for fluoride, there were few studies focusing on the direct association between other trace elements. This study aimed to explore how other trace elements affect dental caries.

Photocatalytic water disinfection is a cutting-edge strategy for effectively sterilizing water in a cost-effective and environmentally friendly manner. A 2D/2D MoS/g-CN heterojunction photocatalyst was specifically designed to improve performance by enhancing the charge separation and reducing the photogenerated carrier loading rate. When exposed to visible light, electron and hole pairs generated on the surface of the heterojunction interacted with O and HO in the environment; this facilitated the production of exogenous reactive oxygen species (ROS) that effectively eliminated the bacteria. With this optimized structure, E. coli and S. aureus were completely inactivated in 20 and 30 min, respectively, under white LED irradiation.

Traditional high-temperature and high-pressure synthesis routes make transition metal nitride (TMN) grains prone to sintering and agglomeration, thus synthesis of architectures with high specific surface area and pore volume is an urgent problem to be solved for the applications of TMNs. Here, a general single-source precursor route is designed to synthesize cubic-phase γ-MoN multilayered hollow spheres with high specific surface area (191.3 m g) and pore volume (0.69 cm g) under relatively mild conditions. Furthermore, by changing the metal composition of the precursor through ion exchange, a series of TMN (WN, TiN, VN, NbN, MoN/WN, MoN/WN/TiN) multilayer hollow spheres with high specific surface area (178.6-193.7 m g) and pore volume (0.57-0.72 cm g) are prepared. Particle size of precursor is found to be a key factor affecting the crystal phase and composition of molybdenum nitride nanostructures, and hexagonal-phase δ-MoN hierarchical hollow spheres composed of nanosheets are synthesized by adjusting the precursor particle size. The γ-MoN multilayered hollow spheres exhibit enhanced Raman activity for applications in trace detection of polychlorophenol and microplastics.

Excessive use of tetracycline poses risks to human health and the ecological balance, which poses challenges to develop a method for facile and reliable detection of tetracycline. Herein, the MoS QDs@ZIF-8 was prepared through a simple method, serving as an asynchronous response sensor for the naked-eye detection of tetracycline. The photoinduced electron transfer between the composite sensor and target tetracycline led to quench the blue fluorescence emitted by MoS QDs. Hydrogen bond, chelation, π-π stacking and pore effect between the composite sensor and tetracycline made the aggregation of tetracycline, significantly enhancing the intrinsic yellow fluorescence of tetracycline. Moreover, it also exhibited good detection performance for the real samples such as river water, farm wastewater, honey and milk, demonstrating that it was suitable for naked-eye visualization detection in the field. This work provided a novel approach for constructing ratiometric fluorescence sensors with asynchronous response.

Non-tuberculous mycobacteria (NTM) are widespread and found in all biotopes, including caves. Some NTMs are potentially pathogenic, causing serious diseases (mycobacterioses) in both animals and humans. This study assesses the effect of various environmental factors on presence of NTM in guano samples of the greater mouse-eared bat (Myotis myotis) collected in 2020 and 2021 from 68 summer roosts throughout the Czech Republic. NTM presence was evaluated by direct microscopy after Ziehl-Neelsen staining, culture examination and real-time quantitative PCR (qPCR). Environmental factors that could potentially affect NTM presence were obtained through GIS and geochemical analysis. While qPCR confirmed high NTM prevalence in bat guano samples (80.9 %), prevalences by standard microscopy and cultivation were much lower (35.1 % and 25.7 %, respectively). In total, ten Mycobacteria were isolated: M. arupense, M. avium subsp. hominissuis, M. chitae, M. fortuitum, M. gordonae, M. kumamotonense, M. litorale, M. peregrinum, M. terrae and M. terrae complex. While presence of the heavy metals palladium and molybdenum had a significant impact on NTM presence, suggesting heavier NTM infestation at polluted sites, landscape, climate and geochemical parameters did not explain differences in NTM load at different sites, possibly due to the high similarity of habitats chosen by M. myotis throughout the Czech Republic.

The self-assembly of polyoxometalate (POM) clusters remains challenging because they heavily depend on highly sensitive synthetic conditions that produce a vast library of potential building blocks and subunits such that explicit control is hard. This work reports new strategies to construct compressed molybdenum blue (MB) type cluster rings with a new range of giant MB POM clusters {Mo}, {Mo}, {Mo}, and {Mo}. These MB clusters prove the limits of the ring structure archetype, showing that it is possible to compress the ring by 100 metal atoms from 154 to 54 yet keep the electronic structure and ring shape. These structures comprise distorted pentagonal building blocks. The compression of the ring is achieved by using a {MoS} unit and {Mo} bridging units. The {Mo} and {Mo} clusters exhibit a unique closed architecture, and redox studies demonstrate the reduced nature of these clusters.