New Technology (Israel)

CO2 flooding, as a commonly employed enhanced oil recovery (EOR) method today, is characterized by high oil displacement efficiency, environmental friendliness, and economic viability, and has been extensively developed and applied in oil and gas field development. During CO2 flooding operations, gas channeling frequently occurs within the reservoir due to significant permeability contrasts arising from formation heterogeneity, coupled with the low density and viscosity of CO2. This phenomenon can adversely affect the normal productivity of oil wells. With the advancement of CO2 flooding technology, the effective prevention of CO2 channeling has become crucial for improving oil recovery. Gel particle plugging systems, being economically viable and efficient, exhibit favorable stability, adaptability, and strength, leading to significant applications in oilfield development and demonstrating promising prospects for future development. This paper comprehensively reviews the classification and developmental status of gel particle systems used for channeling control in CO₂ flooding. It introduces the mechanisms of several gel particle types, including preformed particle gel, polymer microspheres, and dispersed particle gel, and examines their current development status both domestically and internationally. Furthermore, future research directions and application prospects are discussed.

The rational design of high-performance electrocatalysts toward the methanol oxidation reaction plays a noticeable role in the progress of stimulating the industrial development of direct methanol fuel cells. In this study, ultrafine palladium nanocrystals are in situ confined within the hydrazone-linked covalent organic framework (COF-42)-intercalated Ti3C2Tx MXene nanoarchitectures (Pd/COF-MX) through a facile and robust stereoconstruction strategy. The existence of hydrangea-shaped COF-42 with abundant N species makes it possible to optimize the coordination environments for Pd nanocrystals to facilitate their size confinement and homogeneous dispersion, while the MXene nanosheets afford strong electronic interactions and contemporaneously reduce the overall charge-transfer resistance of the hybrid catalyst. As a result, the emerging Pd/COF-MX nanoarchitectures demonstrate a preferable catalytic methanol electrooxidation performance with an extensive electrochemically active surface area, superior mass activity, and dependable long-term stability, significantly outperforming the conventional Pd/carbon black, Pd/carbon nanotube, Pd/reduced graphene oxide, and Pd/MXene catalysts. Density functional theory simulation additionally discloses that the functionalization of COF-42 enables a stronger atomic interaction with the Pd component, which induces an obvious left shift of its d-band center and leads to a weaker adsorption ability toward the CO molecule.

Redox mediators (RMs) have shown promise in enhancing Li-O2 battery cycling stability by reducing overpotential. However, their application is hindered by the shuttle effect, leading to RM loss and Li anode corrosion. Here, we introduce a polyionic liquid, poly (1-Butyl-3-vinylimidazolium bis(trifluoromethanesulfonylimine)) ([PBVIm]-TFSI) as an additive, showcasing a novel Li anode protection strategy for LiI-mediated Li-O2 batteries. [PBVIm]+ cations migrate to the Li anode, forming a protective cationic shield that promotes uniform Li+ deposition. The addition of [PBVIm]-TFSI enhances the cycling stability, achieving 105 cycles at 200 mA⋅g-1, compared to the cell with LiI which exhibited 38 cycles under the same conditions. Synchrotron X-ray tomography reveals the evolution of this protective layer, providing insights into its formation mechanism, in conjunction with XPS analysis. Our findings offer a new approach to Li anode protection in Li-O2 batteries, emphasizing the critical role of interfacial engineering for battery performance.