High-performance and robust catalysts act as core drivers for advanced oxidation technologies for decontamination of water resources. In this study, we used a facile strategy to prepare magnetic and N-doped carbon nanotubes with cobalt encapsulation (Co–N@CNTs) to catalyze ozone for decomposition of aqueous organic pollutants. By regulating the thermal conditions during the synthesis, the derived Co–N@CNTs manifested maneuvered adsorption capabilities. The embedded Co nanoparticles (NPs) not only afforded carbon nanotubes with a magnetic property but also significantly boosted catalytic ozonation due to the synergistic coupling of the Co interface and N-doped graphitic layer. Formation of such a coordinating structure accelerated electron transfer at the interface and increased the conductivity of surface carbon to coordinate a redox reaction. Density functional theory (DFT) calculations and experimental evidence confirmed that cobalt coupled with graphene with pyridinic N dopants was the most favorable structure, which remarkably enhanced ozone adsorption and its dissociation to generate reactive oxygen species (ROS). Intriguingly, the catalytic ozonation underwent different nonradical regimes dependent on the molecular structures of target organics. In terms of ROS, surface-adsorbed atomic oxygen (*Oad) was responsible for degradation of oxalic acid, while phenolics were primarily degraded by O3 molecules and singlet oxygen (1O2). This study provides a cost-efficient and recyclable carbocatalyst for wastewater decontamination and new insights into the structure–functional relationships in carbon-based advanced oxidation processes.

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A large number of natural cracks exist in shale reservoirs, and the presence of natural cracks weakens the integrity of shale, which is an important factor governing the effectiveness of shale gas extraction. In this paper, shales from the Lower Cambrian Niutitang Formation in northern Guizhou were scanned by electron microscopy, their microstructures were selected for digital image processing, and uniaxial compression numerical tests were conducted on shale models containing different natural crack dips using the rock fracture process system RFPA2D-DIP to study the effects of natural cracks on the mechanical properties and fracture patterns of shales at the microscopic scale. The study shows that the peak strength and elastic modulus of shale increase with increasing natural crack inclination angle. The fracture modes of shale at the microscopic scale can be roughly divided into four categories: similar to I-type fractures (0°), oblique I-type fractures (15°, 45°, 60°, 75°), folded line fractures (30°), and V-type fractures (90°). Natural cracks within shale are found to have a significant effect on the distribution of stress. Acoustic emission can reflect the stress change and rupture process for shales containing natural cracks with different dip angles at the microscopic scale. The presence of natural cracks has a significant effect on the AE energy and fractal dimension. The magnitude of the AE energy increases with increasing stress level and reaches a maximum value at 90°, while the value of the fractal dimension is found to zigzag upwards because the value of the fractal dimension is jointly influenced by both newborn cracks and native natural cracks.

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