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The selective oxidation of saturated C-H bonds has long been a significant challenge in chemical research, with the partial oxidation of cyclohexane (Cy) to KA oil (a mixture of cyclohexanol and cyclohexanone) using molecular oxygen (O2) recognized as one of the most important reactions. In this study, we demonstrate the selective oxidation of cyclohexane via photothermal synergism under solvent-free conditions and in the presence of a co-catalyst system. We have elucidated the synergistic effect of the CeO2/g-C3N4 composite catalyst in the photothermal oxidation of cyclohexane. The CeO2/g-C3N4 composite achieved a cyclohexane conversion of 13% and a KA oil selectivity of 97.5%, surpassing the simple additive effects of photocatalysis and thermal catalysis. Through extensive characterization techniques, we present a detailed mechanistic study. Photo-generated electron–hole pairs facilitate the valence cycling of metals during thermal processes, while heat promotes the efficient utilization of these carriers. Furthermore, lattice oxygen can trap holes, reducing the recombination probability of photo-generated charge carriers. This interaction results in a synergistic effect between light and heat, elucidating the phenomenon of photothermal cooperative catalysis in the composite catalyst. These findings suggest that photothermal co-catalysis holds considerable potential for widespread application in green industrial catalytic processes, offering high selectivity and efficiency in organic transformations. Herein, we synthesized a CeO2/g−C3N4 composite with S−scheme heterojunction as a photothermal catalyst, and employed it for the oxidation of Cy to K−A oil in a solvent−free system. CeO2 demonstrates prominent photothermal synergy, and the addition of g−C3N4 can enhance the utilization of electron–hole pairs. This method significantly improves cyclohexane conversion and KA oil selectivity and exceeds the sum of generations of pure photocatalysis and thermal catalysis. The results provide a mechanistic description for photothermal co−catalysis and demonstrate its potential for widespread use in green industrial catalysis [ABSTRACT FROM AUTHOR]

Rotala rotundifolia is an amphibious aquatic plant that can live in submerged and emergent forms. It is superior in nitrogen and phosphorus removal and has been used as a traditional medicine in China for over a hundred years. In this study, the bioactive constituents from different tissues of submerged and emergent R. rotundifolia at different growth periods were investigated. The response surface method was used to optimize the flavonoids extraction condition. The amount of flavonoids and triterpenoids from different tissues of R. rotundifolia were much higher than tannins and alkaloids. The highest total flavonoids amount from the leaves of submerged R. rotundifolia was 270.92 ± 13.34 mg/g at day 30 (phyllomorphosis finished), 1.8 times that of the emergent form (150.45 ± 15.11 mg/g). The highest triterpenoids content from the submerged and emergent forms was 242.20 ± 11.51 and 163.09 ± 14.87 mg/g at days 90 and 150 (flowering stage), respectively. The optimal flavonoid extraction conditions were: extraction time 50 min, ultrasonic power 333 W, ethanol concentration 79.3%, and a solid–liquid ratio of 1:60. The LC-MS/MS analysis showed that the extracts from submerged and emergent R. rotundifolia contained 26 and 22 flavonoids, respectively. This study provides phytochemical evidence for the further utilization of R. rotundifolia. [ABSTRACT FROM AUTHOR]

Three-dimensional (3D) microstructured biomaterials are favorable in tissue engineering due to their superior guidance to cellular activities. Herein, we developed a 3D microstructured bacterial cellulose (BC) with arranged fibers by controlling Acetobacter xylinum through an electric field (EF) application. The real-time video analysis showed that EF directed the migration of A. xylinum and increased its migration speed with the increased EF. The bacteria quickly changed direction with high motility in response to the switch on/off of the EF. In the long-term electrical stimulation (ES), the growth of A. xylinum was influenced. Likewise, bacterial cells were oriented along the direction of EF while bacteria simultaneously produced nanocellulose, resulting in 3D networks with aligned fibers. The prepared 5 mA-BC hydrogels presented the ordered 3D microstructure with higher fiber alignment, diameter and flexibility than that of NO EF-BC hydrogels. The in vitro biological evaluation demonstrated that the 5 mA-BC hydrogels were biocompatible whereon NIH3T3 cells proliferated along the direction of fiber alignment. These findings demonstrate that ES provides a promising strategy for the natural fabrication of aligned 3D microstructured BC to guide cellular activities for tissue regeneration. [ABSTRACT FROM AUTHOR]

Highlights: The cellulosed-based macrofibers possess super-strong tensile strength of 449 MPa and excellent electrical conductivity of 5.32 S cm−1. The cellulosed-based macrofiber can be degraded within 108 h in the cellulase solution. The designed fabric-based triboelectric nanogenerator (TENG) shows a maximum output power of 352 μW, which can effectively drive commercial electronics. The designed fabric-based TENG as self-powered sensors can effectively monitor the human movement of walking, running, jumping, arm lifting, arm bending, and leg lifting.Electronic fibers used to fabricate wearable triboelectric nanogenerator (TENG) for harvesting human mechanical energy have been extensively explored. However, little attention is paid to their mutual advantages of environmental friendliness, mechanical properties, and stability. Here, we report a super-strong, biodegradable, and washable cellulose-based conductive macrofibers, which is prepared by wet-stretching and wet-twisting bacterial cellulose hydrogel incorporated with carbon nanotubes and polypyrrole. The cellulose-based conductive macrofibers possess high tensile strength of 449 MPa (able to lift 2 kg weights), good electrical conductivity (~ 5.32 S cm−1), and excellent stability (Tensile strength and conductivity only decrease by 6.7% and 8.1% after immersing in water for 1 day). The degradation experiment demonstrates macrofibers can be degraded within 108 h in the cellulase solution. The designed fabric-based TENG from the cellulose-base conductive macrofibers shows a maximum open-circuit voltage of 170 V, short-circuit current of 0.8 µA, and output power at 352 μW, which is capable of powering the commercial electronics by charging the capacitors. More importantly, the fabric-based TENGs can be attached to the human body and work as self-powered sensors to effectively monitor human motions. This study suggests the potential of biodegradable, super-strong, and washable conductive cellulose-based fiber for designing eco-friendly fabric-based TENG for energy harvesting and biomechanical monitoring. [ABSTRACT FROM AUTHOR]

The interface properties of CeAlO3 (110)/NbC (111) were calculated by the first-principles and the refinement of CeAlO3 on NbC in hypereutectic Fe–Cr–C–Nb hardfacing alloy was demonstrated by experiments. The calculation results show that the mismatch of CeAlO3 (110)/NbC (111) is 7.2%, which indicates that the interface between CeAlO3 (110) and NbC (111) is a semi-coherent interface. Then, 11 layer CeAlO-terminated CeAlO3 (110) surface was selected to build interface with NbC (111) surface, whose surface energy is 0.380 eV/Å2. Because of the instability of O-terminated CeAlO3 (110) surface, its surface energy cannot achieve convergence. 6 kinds of interfaces between CeAlO3 (110)/NbC (111) were constructed, in which, interface-3 is the most stable with strong ionic and covalent bonds. Theoretically, CeAlO3 can act as the heterogeneous nucleation site for NbC. The experimental results show that the (Cr, Fe)7C3, NbC and γ-Fe phases exist in hypereutectic Fe–Cr–C–Nb–CeAlO3 hardfacing alloys. When CeAlO3 was added into the alloy, NbC can be refined. [ABSTRACT FROM AUTHOR]

Three kinds of hypereutectic Fe–Cr–C hardfacing coatings were designed to research the refinement effect and heterogeneous nucleation mechanism of NbC on nano-Y2O3 in the coatings. The microstructure and elemental maps of Fe–Cr–C–Nb–Y2O3 coating were investigated by field emission scanning electron microscope. The phase structures of the coating and heterogeneous nucleation were researched by transmission electron microscope (TEM). The lattice mismatch between Y2O3 and NbC was computed by Bramfitt's two-dimensional lattice mismatch theory. The adhesive strength, interface energy and electronic properties of Y2O3(111)/NbC(110) interfaces were calculated by a first-principles method. The bonding characteristics of heterogeneous nucleation interfaces were analyzed by charge density difference, electron localization function and Bader charge population. The experimental results show that the primary M7C3 can be refined by NbC, when Nb additive was added into the Fe–Cr–C coating. When nano-Y2O3 and Nb additive were added into the coating simultaneously, the primary M7C3 can be further refined. The SEM results show that NbC can be effective heterogeneous nucleation substrate of the primary M7C3 and there is a compound containing rare earth (RE) element Y in NbC particle. The TEM results verified the RE compound in NbC particle is Y2O3, and they combine together tightly. The calculation results indicate that the two-dimensional lattice mismatch of Y2O3(111)/NbC(110) interface is 6.8%, which reveals that Y2O3 meets the geometric condition to act as a medium-effective heterogeneous nucleation substrate of NbC. In all interface models, the adhesive strength of O-Bridge model is the largest (Wad = 9.75 J/m2) and its stability is the best (γ = − 0.87 J/m2). The major bond type of O-terminated interfaces is covalent one. Actually, the interfacial energy of O-terminated interface is negative, which reveals that their formation process is a process of energy reduction and structure stabilization. It means Y2O3 and NbC can form stable interface structure. It can be predicted that the heterogeneous nucleation occurs preferably on the O-terminated interfaces. Therefore, Y2O3 can serve as an effective heterogeneous nucleation substrate of NbC to refine it. [ABSTRACT FROM AUTHOR]