Carbon dioxide (CO2) injection is a promising strategy for enhancing shale oil recovery while enabling geological carbon storage. In this study, non-equilibrium molecular dynamics (NEMD) simulations were employed to investigate CO2-driven shale oil transport in kerogen nanopores with complex surface characteristics. The distribution and migration behaviors of multiphase shale oil were analyzed, and the effects of pore size, temperature, and injection pressure on fluid flow and CO2 sequestration were systematically evaluated. The results show that shale oil forms three distinct adsorption layers within kerogen nanopores, with the first layer exhibiting a peak density of approximately 1.13 g/cm3, which is about 1.85 times higher than that in the free region. The irregular kerogen surface increases the resistance to shale oil desorption, resulting in slower CO2-driven displacement compared with smooth graphene pores. Increasing pore size, temperature, and injection pressure significantly promotes shale oil desorption and enhances CO2 storage capacity. For example, when the pore size increases from 2 nm to 5 nm, the shale oil adsorption fraction decreases markedly while CO2 storage increases significantly. Temperature also plays an important role in regulating adsorption and sequestration behavior. Overall, this study reveals the molecular-scale mechanisms governing CO2-enhanced shale oil mobilization and carbon sequestration in kerogen nanopores, providing theoretical insights for optimizing CO2 injection strategies in shale reservoirs.

The synergistic effect of nanoparticles can effectively improve the tribological performances of base oils. In this study, a novel lubricant additive by embedding 2D FeOCl on 2D Zn - MOF was reported for the first time in order to boost the tribological performances of polyethylene glycol (PEG200). The FeOCl/Zn - MOF prepared by a facile microwave assisted strategy was found to be a typical flower-like appearance, where FeOCl nanosheets decorated on the surface of Zn - MOF sheets. Owing to the electron transfer and synergistic effect between FeOCl and Zn - MOF, the novel FeOCl/Zn - MOF effectively reduced the coefficient of friction by 48 % and wear scar diameter by 88 % at the loading of 0.4 wt% FeOCl/Zn - MOF in the base oil. The work suggests the face-to-face combination of FeOCl and Zn - MOF for enhanced tribological performances, representing a new strategy to prepare efficient lubricant additives using assembled 2D nanomaterials.

The purpose of this study is to prepare graphene/FeOCl (G/FeOCl) heterojunctions via a microwave-pyrolysis approach and probe into the synergistic lubrication of G with FeOCl in liquid paraffin (LP). The morphology and chemical composition of specimens were analysed by utilizing scanning electron microscopy (SEM) with energy dispersive spectroscopy (EDS), X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, and X-ray photoelectron spectroscopy (XPS) techniques. The tribological property of G/FeOCl was determined, and the interaction between the G/FeOCl heterojunction and friction pair was carried out through simulation calculations. The results indicated that neither G nor FeOCl significantly improved the lubrication performance of LP. However, together with FeOCl, G as lubrication additives greatly improved the lubrication performance of LP. Under the load of 1.648 GPa, the mean friction coefficient and wear scar diameter of LP containing 0.20 wt% G/FeOCl were 66.1% and 44.7% inferior to those of pure LP, respectively. Scanning electron microscopy (SEM) and elemental mapping analyses of worn scars revealed the formation of G/FeOCl layer tribofilms that prevent direct contact between metals. In addition, the high interfacial energy between graphene and FeOCl calculated based on first-principles density functional theory (DFT) further confirmed that graphene and FeOCl simultaneously form friction films with wear resistance and wear reduction effect at the friction interface, which is consistent with the experimental results. This study, therefore, provides a pathway for low-friction lubricants by deploying G/FeOCl two-dimensional material systems.

In this study, a novel lubricant additive hybridizing pyrolytic graphene and serpentine was reported for the first time to enhance the tribological performance of paraffin oil. The in situ produced pyrolytic graphene from pyrolysis of critic acid was observed to be intercalated into the interlayer of serpentine sheets. The structure, morphology and chemical composition of the composite lubricant additives were characterized by scanning electron microscope, X-ray diffractometer and Fourier transform infrared spectroscopy. In addition, the anti-wear, friction-reduction and self-healing mechanisms of the hybrid lubricant additive, owing to its activity on the friction interface, were disclosed by exploring the morphology and components of the wear scar after friction. The tribological results revealed that introducing a small amount of pyrolytic graphene/serpentine lubricant additive (0.2 wt%) to the base oil could effectively reduce the friction coefficient (~87%) and wear loss (~71%) in comparison with neat paraffin oil. First-principles calculations based on density functional theory were further performed to uncover the lubrication mechanism of the hybrid. Therefore, the pyrolytic graphene/serpentine hybrid reported herein represents a new strategy to prepare high efficient lubricant additive.

A novel carbon sphere (CS)@metallographic molybdenum disulfide (1 T-MoS2) hybrid was prepared by a straightforward one-step hydrothermal method and its synergistic effect on the tribology of polyethylene glycol 200 (PEG200) was reported. Systematical characterizations exhibited 1 T-MoS2 sheets were evenly anchored on the CS surface. Tribological results showed the friction coefficient of pure PEG200 oil decreased by 43% with adding 0.3125 wt% CS@ 1 T-MoS2. Optical images showed the diameters of wear marks were significantly reduced from 1860 mu m for neat base oil to 880 mu m for CS@ 1 T-MoS2. It was believed that the synergy between CS and 1 T-MoS2 played the crucial role in the friction reducing and anti-wear. Therefore, this work provides a facile approach to preparing lubricating additives by decorating 1 T-MoS2 on CS.

In our research described in this paper 1T Phase Molybdenum Disulfide/Polyethylene Glycol (200) (1T-MoS2/PEG) was studied as a lubricant for steel-steel contact with the goal of minimizing or eliminating galling. The morphology and structures of 1T-MoS2 were analyzed by various techniques, such as scanning electron microscopy (SEM), X-ray diffraction spectroscopy (XRD), and X-ray photoelectron spectroscopy (XPS). In addition, the friction performance of oleic acid (OA) modified 1T-MoS2 as a lubricants additive for PEG was investigated. The results of the friction test indicated that the average friction coefficient and wear scar diameter of PEG containing 0.1875 wt% 1T-MoS2 were 14.30% and 46.90% less than those of pure PEG, respectively. However, those of 0.1875 wt% 1T-MoS2/PEG modified by OA as lubrication additives were 47.83% and 56.79% lower than those of pure PEG. 1T-MoS2 nanoparticles can not only fill the inherent grooves on the surface of the steel ball, but also form a friction lowering film on the friction interface, thus reducing friction and wear, which was seen from the results of scanning electron microscopy (SEM) and element mapping of the wear scar. This study, most importantly, provides a foundation for the use of 1T-MoS2/PEG and OA/1T-MoS2/PEG as effective lubricants to reduce the friction problems in the mechanical industry.

Carbon/aramid fabric composite coatings modified with boron nitride of single layer were fabricated through a dip-coating method. The composite coatings were cured with successive heating processes in an oven. The friction and wear properties of those as-prepared coatings were studied on a block-on-ring tester. The obtained results showed that the wear life of the coatings increased obviously after inclusion of boron nitride of single layer; however, the values of friction coefficients of the coatings almost remained constant. The optimal loadings of boron nitride of single layer in our experiments was 5 wt.%, and the wear life of the modified coating increased by ca. 360% compared with that of pristine fabric composite coating. The worn morphology of the sliding surface for both pristine fabric coating and the composite coatings filled with boron nitride of single layer was discussed, and the wear mechanisms were illuminated.

Monomer casting polyamide 6 (MC PA6)/boron nitride of single layer (SBN) nanocomposites were successfully synthesized by in situ ring-opening polymerization. SBN was prepared by sonication assisted with solution beforehand. Studies on frictional and wear performance of the nanocomposites were carried out on a block-on-ring tester. The results showed that the nanocomposites had lower wear rates and friction coefficients in comparison with neat MC PA6. The incorporation of 0.25 wt% SBN into MC PA6 significantly reduced wear and friction under dry sliding; however, with further increasing the SBN loading, both wear rate and friction coefficient began to increase. The SEM micrographs of the worn surface revealed their friction and wear mechanisms. Pure MCPA6 was characterized by severe lamellar spalling with adhesive wear being the major wear form which caused high friction and wear. The wear modes of the nanocomposites became mainly abrasive wear with lower content of SBN and displayed fatigue wear with higher content of SBN. The morphology of a uniform transfer film on the counterpart ring and fine wear debris for the nanocomposites corresponded to the improved tribological performance.