Green Energy & Environment最新文献

Emerging excessive greenhouse gas emissions pose great threats to the ecosystem, which thus requires efficient CO₂ capture to mitigate the disastrous issue. In this report, large molecular size bisphenol A ethoxylate diacrylate (BPA) was employed to crosslink poly (ethylene glycol) methyl ether acrylate (PEGMEA) via the green and rapid UV polymerization strategy. The microstructure of such-prepared membrane could be conveniently tailored by tuning the ratio of the two prepolymers, aiming at obtaining the optimized microstructures with suitable mesh size and PEO sol content, which was approved by a novel low-field nuclear magnetic resonance technique. The optimum membrane overcomes the trade-off challenge: dense microstructures lower the gas permeability while loose microstructures lower high-pressure-resistance capacity, realizing a high CO₂ permeability of 1711 Barrer and 100-h long-term running stability under 15 atm. The proposed membrane fabrication approach, hence, opens a novel gate for developing high-performance robust membranes for CO₂ capture.

Rapid capacity decay and sluggish reaction kinetics are major barriers hindering the applications of manganese-based cathode materials for aqueous zinc-ion batteries. Herein, the effects of crystal plane on the in-situ transformation behavior and electrochemical performance of manganese-based cathode is discussed. A comprehensive discussion manifests that the exposed (100) crystal plane is beneficial to the phase transformation from tunnel-structured MnO₂ to layer-structured ZnMn₃O₇·3H₂O, which plays a critical role for the high reactivity, high capacity, fast diffusion kinetics and long cycling stability. Additionally, a two-stage zinc storage mechanism can be demonstrated, involving continuous activation reaction and phase transition reaction. As expected, it exhibits a high capacity of 275 mAh g⁻¹ at 100 mA g⁻¹, a superior durability over 1000 cycles and good rate capability. This study may open new windows toward developing advanced cathodes for ZIBs, and facilitate the applications of ZIBs in large-scale energy storage system.

Lignin waste from the papermaking and biorefineries industry is a significantly promising renewable resource to prepare advanced carbon materials for diverse applications, such as the electrodes of supercapacitors; however, the improvement of their energy density remains a challenge. Here, we design a green and universal approach to prepare the composite electrode material, which is composed of lignin-phenol-formaldehyde resins derived hierarchical porous carbon (LR-HPC) as conductive skeletons and the self-assembly manganese cobaltite (MnCo₂O₄) nanocrystals as active sites. The synthesized C@MnCo₂O₄ composite has an abundant porous structure and superior electronic conductivity, allowing for more charge/electron mass transfer channels and active sites for the redox reactions. The composite shows excellent electrochemical performance, such as the maximum specific capacitance of ∼726 mF cm⁻² at 0.5 mV s⁻¹, due to the significantly enhanced interactive interface between LR-HPC and MnCo₂O₄ crystals. The assembled all-solid-state asymmetric supercapacitor, with the LR-HPC and C@MnCo₂O₄ as cathode and anode, respectively, exhibits the highest volumetric energy density of 0.68 mWh cm⁻³ at a power density of 8.2 mW cm⁻³. Moreover, this device shows a high capacity retention ratio of ∼87.6% at 5 mA cm⁻² after 5000 cycles.

Graphene-based nanocatalysts have appealed much interest as advanced electrocatalysts toward energy conversion reactions due to their outstanding electrocatalytic performance from the distinctive chemical composites and strong synergistic effects. Aiming to better understand the role of graphene played in enhancing the catalytic performance and offer guidance for fabricating more efficient graphene-based electrocatalysts, we herein summarize the remarkable achievements of graphene-based electrocatalysts for energy-conversion-related reactions. Started by discussing applications of graphene in the electrocatalytic reactions, we have manifested the crucial role of graphene played in promoting the catalytic performance. Subsequently, many representative graphene-based catalyst hybrids for electrocatalytic reactions are also overviewed, showing many effective strategies for the fabrication of more efficient graphene-related materials for the practical application. Finally, the perspective insights and challenging issues are also concluded to provide directions for the future development.

Although oily wastewater treatment realized by superwetting materials has attracted heightened attention in recent years, how to treat enormous-volume emulsion wastewater is still a tough problem, which is ascribed to the emulsion accumulation. Herein, to address this problem, a material is presented by subtly integrating chemical demulsification and 3D inner-outer asymmetric wettability to a sponge substrate, and thus wettability gradient-driven oil directional transport for achieving unprecedented enormous-volume emulsion wastewater treatment is realized based on a “demulsification-transport” mechanism. The maximum treatment volume realized by the sponge is as large as 3 L (2.08 × 10⁴ L per cubic meter of the sponge) in one cycle, which is about 100 times of the reported materials. Besides, owing to the large pore size of the sponge, 9000 L m² h⁻¹ (LMH) separation flux and 99.5% separation efficiency are realized simultaneously, which overcomes the trade-off dilemma. Such a 3D inner-outer asymmetric sponge displaying unprecedented advantage in the treatment volume can promote the development of the oily wastewater treatment field, as well as expand the application prospects of superwetting materials, especially in continuous water treatment.

Bronze phase titanium dioxide (TiO₂(B)) could be a promising high-power anode for lithium ion battery. However, TiO₂(B) is a metastable material, so the as-synthesized samples are inevitably accompanied by the existence of anatase phases. It has been found that the TiO₂(B)'s purity is positively correlated with its electrochemical performance. Herein, we have established an accurate quantification of the TiO₂(B)/anatase ratio, by figuring out the function between the purity of TiO₂(B) phase in the high purity range and its Raman spectra features in combination of the calibration by the synchrotron radiation X-ray diffraction (XRD). Compared with the time-consuming electrochemical method, the rapid, sensitive and non-destructive features of Raman spectroscopy have made it a promising candidate for determining the purity of TiO₂(B). Further, the correlations developed in this work should be instructive in synthesizing pure TiO₂(B) and furthermore optimizing its electrochemical charge storage properties.

The extraction of lithium from salt lakes or seawater has attracted worldwide attention because of the explosive growth of global demand for lithium products. The LiMn₂O₄-based electrochemical lithium recovery system is one of the strongest candidates for commercial application due to its high inserted capacity and low energy consumption. However, the surface orientation of LiMn₂O₄ that facilitates Li diffusion happens to be prone to manganese dissolution making it a great challenge to obtain high lithium inserted capacity and long life simultaneously. Herein, we address this problem by designing a truncated octahedral LiMn₂O₄ (Tr-oh LMO) in which the dominant (111) facets minimize Mn dissolution while a small portion of (100) facets facilitate the Li diffusion. Thus, this Tr-oh LMO-based electrochemical lithium recovery system shows excellent Li recovery performance with high inserted capacity (20.25 mg g⁻¹ per cycle) in simulated brine. In addition, the dissolution rate of manganese per 30 cycles is only 0.44% and the capacity maintained 85% of the initial after 30 cycles. These promising findings accelerate the practical application of LiMn₂O₄ in electrochemical lithium recovery.

Developing high efficient Pd-based electrocatalysts for oxygen reduction reaction (ORR) is still challenging for alkaline membrane fuel cell, since the strong oxygen adsorption energy and easy agglomerative intrinsic properties. In order to simultaneously solve these problems, Pd/Co₃O₄–N–C multidimensional materials with porous structures is designed as the ORR catalysts. In details, the ZIF-67 with polyhedral structure was firstly synthesized and then annealed at high-temperature to prepare the N-doped Co₃O₄ carbon-based material, which was used to homogeneously confine Pd nanoparticles and obtained the Pd/Co₃O₄–N–C series catalysts. The formation of Co–N and C–N bond could provide efficient active sites for ORR. Simultaneously, the strong electronic interaction in the interface between the Pd and N-doped Co₃O₄ could disperse and avoid the agglomeration of Pd nanoparticles and ensure the exposure of active sites, which is crucial to lower the energy barrier toward ORR and substantially enhance the ORR kinetics. Hence, the Pd/Co₃O₄–N–C nanocompounds exhibited excellent ORR catalytic performance, ideal Pd mass activity, and durability in 0.1 mol L⁻¹ KOH solution compared with Co₃O₄–N–C and Pd/C. The scalable synthesis method, relatively low cost, and excellent electrochemical ORR performance indicated that the obtained Pd/Co₃O₄–N–C electrocatalyst had the potential for application on fuel cells.