With the global demand for clean energy and efficient energy storage technologies continually rising,lithium-ion capacitors (LICs) are being increasingly utilized in electric vehicles,portable electronic devices,and large-scale energy storage systems. Conductive additives,as essential components of electrode materials,play a crucial role in enhancing the electrochemical performance of LICs by constructing efficient conductive networks.This review provides a comprehensive overview of the roles, types,and effects of conductive additives in LICs,with a particular emphasis on the application examples and advantages of emerging additives such as graphene and carbon nanotubes.Furthermore,the synergistic effects of composite conductive additives are discussed,along with an analysis of the current industrial status and future development trends of conductive additives.This review aims to offer theoretical insights and practical references for the optimized design and application development of LICs.
Hydrogen production via ammonia decomposition is a crucial pathway toward achieving a "carbon-neutral society", and its catalytic efficiency is significantly influenced by the regulation of support materials. Based on the similar electronic structures of Al and Y elements, which belong to the main group and the subgroup (transition metal group) respectively, the differentiation mechanisms of Y?O? and Al?O? supports in cobalt-based catalysts were systematically compared.Catalyst characterization was performed using XRD, BET, SEM, XPS, H2-TPR, and NH3-TPD. The results show that although both Al and Y are trivalent, Y, as a rare-earth transition element, possesses a unique 4f electron configuration, which endows Y2O3 with richer oxygen vacancies and stronger electron-donating ability, significantly promoting the formation and dispersion of active Co2+ species. The 10Co/Y2O3 catalyst achieves an ammonia conversion of 100% at 700 ℃, and its specific surface area activity is 3.2 times that of 10Co/Al2O3. Although Al2O3 exhibits higher specific surface area and thermal stability, the spinel phase CoAl2O4 formed between the main-group element Al and Co shows low activity. This study provided new insights for the rational design of catalysts based on the periodic law.
Electrocatalytic water splitting for hydrogen production is a crucial technological approach for renewable energy storage and utilization. Based on the hydrogen evolution reaction mechanism, this paper systematically reviews the structural evolution of hydrogen evolution reaction catalysts from bulk materials, multidimensional nanostructures, to nanoclusters, single atoms, and single atom-nanocluster synergistic systems from the perspective of size regulation of active components. Extensive literature studies demonstrate that as the size of active species decreases, the metal atom utilization efficiency of catalysts significantly improves. Nanocluster and single atom catalysts exhibit intrinsic activity surpassing traditional bulk materials due to their unique quantum size effects and coordination environments while reducing noble metal usage. Notably, the synergistic system of single atoms and nanoclusters effectively promotes water molecule dissociation and hydrogen desorption through a dual-site mechanism, significantly enhancing alkaline hydrogen evolution reaction kinetics. Based on this, future research should focus on multi-scale structural regulation and precise synthesis, deeply elucidate the dynamic structure-activity relationships during the reaction process, and thereby design low-cost catalysts with high activity, high stability, and broad pH adaptability.
The demand for oxygen-containing plastics has grown rapidly due to their outstanding comprehensive properties, rendering the disposal of plastic waste an urgent environmental challenge. Among existing treatment methods, catalytic hydrogenolysis within chemical recycling is recognized as a green strategy aligned with sustainable development, as it can directionally convert oxygen-containing plastics into high-value chemicals (e.g., monomers, fuels). Homogeneous catalysts possess notable potential in this field by virtue of advantages such as mild reaction conditions and controllable product selectivity. This review systematically summarizes recent research progress in homogeneous catalysts for the catalytic hydrogenolysis of oxygen-containing plastics, focusing on catalyst design, reaction condition optimization, product regulation mechanisms, and structure-activity relationships, which offers theoretical reference for advancing the industrialization of this technology.
This study is dedicated to enhancing the photocatalytic performance of rod-like ZnO via surface modification with Pd and PdCu nanoparticles, with the goal of extending its spectral response and suppressing the recombination of photogenerated charge carriers. Rod-shaped ZnO was synthesized via the solvothermal method, with the total metal mass fraction controlled at 3%. The structural and optical properties of Pd/ZnO and PdCu/ZnO were comparatively investigated and correlated with their catalytic performance. Experimental results demonstrated that both Pd and PdCu modifications triggered a localized surface plasmon resonance effect, which facilitated the separation of photogenerated electron–hole pairs and enhanced visible-light harvesting efficiency. Compared with PdCu/ZnO, although Pd/ZnO exhibits a wider band gap and a lower proportion of oxygen vacancies, it demonstrates a stronger separation capability for photogenerated carriers and thus achieves higher degradation efficiency. After 30 minutes of light irradiation, the RhB degradation rate of Pd/ZnO reaches 99.7%.Moreover,Pd/ZnO possesses excellent stability, with the degradation rate remaining at 96.9% after five cycling tests.
Inspection of long-term operating atmospheric and vacuum distillation units reveals that non-uniform thinning frequently occurs in the outlet pipeline of the atmospheric tower overhead air cooler, with local thinning rates exceeding 30%. The risk of pipeline perforation and rupture increased significantly, which could easily cause overhead oil and gas leakage. Analyses were carried out from some dimensions including pipeline material, operating condition and process anticorrosion technology. The results show that pipeline wall thinning primarily originates from erosion corrosion induced by gas-liquid two-phase flow, as well as under-deposit corrosion resulting from ammonium salt crystal deposition in the low-temperature zone at the atmospheric tower overhead. In response to this problem, a series of anti-corrosion optimization plans were proposed, including improving pipeline materials, introducing ultrasonic-electric desalination synergistic demulsification technology, strengthening crude oil demulsification to reduce the amount of chloride ions carried, expanding overhead water injection volume, and adding online desalination facilities. Relevant measures can effectively mitigate the corrosion rate of the tower overhead system, extend the service life of the equipment, and provide technical support for the safe, stable, and long-term operation of atmospheric and vacuum distillation unit.
Through the combination of imbibition and displacement,the impact of the combined action of imbibition and displacement on reservoir pressure and fluid flow during the soaking process after reverse hydraulic fracturing assisted oil displacement in low-permeability reservoirs was explored.A semi-analytical mathematical model for productivity prediction of reverse hydraulic fracturing assisted oil displacement is established,considering interlayer heterogeneity.An analysis was conducted on the changes in the flow field before and after soaking.Parametric studies are conducted to reveal the effects of permeability ratio, total injection volume,injection rate and soaking time on the pressure swept range,saturation swept range and cumulative oil production of each layer after soaking.The research results indicate that soaking well after hydraulic fracturing assisted oil displacement can enhance the energy enhancement effect of reverse hydraulic fracturing assisted oil displacement,further expand the affected area,and thus utilize more geological reserves.To achieve efficient development through hydraulic fracturing assisted oil displacement,it is recommended to consider layered mining when the permeability ratio is greater than 25.Meanwhile,the soaking time should be controlled within 10~15 days,with a properly reduced injection rate and increased total injection volume.
To address the problems of channeling through existing fractures, uneven reservoir stimulation,and limited recovery enhancement during reservoir development,the parameters of temporary plugging and directional fracturing were optimized through physical simulation experiments, and the fracture propagation laws were systematically analyzed.The effects of the mass ratio between granular temporary plugging agents (particle size: 0.31~0.34 cm) and powdery temporary plugging agents (particle size:0.10~0.18 cm), the total mass of temporary plugging agents,and the fracturing fluid injection rate on the plugging performance were investigated. Combined with large-scale physical simulation experiments, the fracture deflection characteristics were further analyzed. The results indicate a synergistic optimal relationship among the parameters.When the mass ratio of the two agents is 5∶5, the fracturing fluid injection volume is 2 000 mL, the total agent dosage is 50 g, and the injection rate is 100 mL/min,the sealing effect is optimal,with the sealed zone withstanding a stable pressure of 9.54 MPa and forming in just 81 s. In the large-scale physical model, the fracture deflection angle reached a maximum of 167.5° under this parameter combination, effectively blocking the propagation of existing fractures and forcing the fracturing fluid to expand into undeveloped areas of the reservoir. This study clarifies the optimal parameter system and fracture propagation mechanism,providing reliable experimental evidence and theoretical support for the in-situ remediation of existing fractures.
