Mixed‑Dimensional Assembly Strategy to Construct Reduced Graphene Oxide/Carbon Foams Heterostructures for Microwave Absorption,Anti‑Corrosion and Thermal Insulation

Considering the serious electromagnetic wave(EMW)pollution problems and complex application condition,there is a pressing need to amalgamate multiple functionalities within a single substance.However,the effective integration of diverse functions into designed EMW absorption materials still faces the huge challenges.Herein,reduced graphene oxide/carbon foams(RGO/CFs)with two-dimensional/three-dimensional(2D/3D)van der Waals(vdWs)heterostructures were meticulously engineered and synthesized utilizing an efficient methodology involving freeze-drying,immersing absorption,secondary freeze-drying,followed by carbonization treatment.Thanks to their excellent linkage effect of amplified dielectric loss and optimized impedance matching,the designed 2D/3D RGO/CFs vdWs heterostructures demonstrated commendable EMW absorption performances,achieving a broad absorption bandwidth of 6.2 GHz and a reflection loss of-50.58 dB with the low matching thicknesses.Furthermore,the obtained 2D/3D RGO/CFs vdWs heterostructures also displayed the significant radar stealth properties,good corrosion resistance performances as well as outstanding thermal insulation capabilities,displaying the great potential in complex and variable environments.Accordingly,this work not only demonstrated a straightforward method for fabricating 2D/3D vdWs heterostructures,but also outlined a powerful mixeddimensional assembly strategy for engineering multifunctional foams for electromagnetic protection,aerospace and other complex conditions.

A hefty target of reducing the intensity of carbon dioxide emissions

At the end of January, China formally handed over the report on pollution reduction targets to the United Nations.

Management Strategies and Their Evaluation for Carbon Sequestration in Cropland

In order to deal with the global change and to reduce emission of greenhouse gas, a number of countries have strengthened studies on carbon sequestration in cropland. Carbon sequestration in cropland is not only an important component for the global carbon stock, but also is the most active part to sequestrate the carbon in soil from atmosphere. In this sense, it is of necessity and significance to strengthen the study on management of carbon sequestration in cropland. Based on the main factors affecting carbon cycle in agro-ecosystems, this paper summarizes the relevant management measures to strengthen the capacity of reducing emission of carbon and increasing the carbon sequestration in cropland, and evaluates the effects of these measures after being implemented at a regional extent.

Catalytic Performance of Carbon Materials Supported Pd Nanoparticles in Selective Hydrogenation of Acetylene

Pd/C catalysts were prepared by deposited Pd nanoparticles （NPs） on different carbon supports including activated carbon （AC）, graphite oxide （GO）, and reduced graphite oxide （rGO） using sol-immobilization method. Through transmission electron microscopy, powder X-ray di raction, and X-ray photoelectron spectroscopy, the role of the carbon supports for the catalytic performances of Pd/C catalysts was examined in selective hydrogenation of acetylene. The results indicate that Pd/AC exhibited higher activity and selectivity than Pd/GO and Pd/rGO in the gas phase selective hydrogenation of acetylene. Thermal and chemical treatment of AC supports also have some effect on the catalytic performance of Pd/AC catalysts. The differences in the activity and selectivity of various Pd/C catalysts were partly attributed to the metal-support interaction.

Enhanced cycle performance of Li/S battery with the reduced graphene oxide/activated carbon functional interlayer

The high-energy lithium/sulfur(Li/S) battery has become a very popular topic of research in recent years due to its high theoretical capacity of 1672 m Ah/g. However, the polysulfide shuttle effect remains of great concern with a great number of publications dedicated to its mitigation. In this contribution, a three-dimensional(3D) reduced graphene oxide/activated carbon(RGO/AC) film, synthesized by a simple hydrothermal method and convenient mechanical pressing, is sandwiched between the separator and the sulfur-based cathode, acting as a functional interlayer to capture and trap polysulfide species. Consequently, the Li/S cell with this interlayer shows an impressive initial discharge capacity of 1078 m Ah/g and a reversible capacity of 655 m Ah/g even after 100 cycles. The RGO/AC interlayer impedes the movement of polysulfide while providing unimpeded channels for lithium ion mass transfer. Therefore, the RGO/AC interlayer with a well-designed structure represents strong potential for high-performance Li/S batteries.

Hybrid of Quaternary Layered Double Hydroxides and Carbon Nanotubes for Oxygen Evolution Reaction

Highly active electrocatalysts based on Layered Double Hydroxides(LDH)towards oxygen evolution reactions(OER)are required for the applications of renewable energy-conversion technology.The improvement of conductivity and electron-transporting capability for LDH materials remains an enormous challenge yet.Here,we synthesized carbon nanotube supported quaternary FeCoNiW-LDH ultrathin nanosheets with 1 nm thickness via one-pot hydrothermal methods,which exhibit enhanced OER activity due to the synergistic effect of modified CNTs and doped W^6+onto LDH nanosheets catalysts.The loaded carbon nanotubes can directly result in the improved conductivity.In addition,W^6+doping in LDH can modify the electronic structure and further enhance the conductivity of electrocatalysts.FeCoNiW-LDH/CNT exhibits a small overpotential(258 mV)at a current density of 10 mA·cm^–2 and low Tafel slope(41 mV decade^–1)towards OER in alkaline solutions,outperforming the noble metal RuO2 catalysts.

Lithiophilic N-doped carbon bowls induced Li deposition in layered graphene film for advanced lithium metal batteries

Lithium(Li)metal with high theoretical capacity and low electrochemical potential is the most ideal anode for next-generation high-energy batteries.However,the practical implementation of Li anode has been hindered by dendritic growth and volume expansion during cycling,which results in low Coulombic efficiency(CE),short lifespan,and safety hazards.Here,we report a highly stable and dendrite-free Li metal anode by utilizing N-doped hollow porous bowl-like hard carbon/reduced graphene nanosheets(CB@rGO)hybrids as three-dimensional(3D)conductive and lithiophilic scaffold host.The lithiophilic carbon bowl(CB)mainly works as excellent guides during the Li plating process,whereas the rGO layer with high conductivity and mechanical stability maintains the integrity of the composite by confining the volume change in long-range order during cycling.Moreover,the local current density can be reduced due to the 3D conductive framework.Therefore,CB@rGO presents a low lithium metal nucleation overpotential of 18 mV,high CE of 98%,and stable cycling without obvious voltage fluctuation for over 600 cycles at a current density of 1 mA cm^(-2).Our study not only provides a good CB@rGO host and pre-Lithiated CB@rGO composite anode electrode,but also brings a new strategy of designing 3D electrodes for those active materials suffering from severe volume expansion.

Reduced Graphene Oxide/Carbon Fiber Composite Membrane for Self-floating Solar-thermal Steam Production

Solar-thermal water evaporation has attracted increasing attention owing to the promising potential to solve the global clean water and energy crisis.But,the development of this strategy is limited by the lack of materials with high solar-thernal conversion efficiency,local heating of superficial water,easy preparation and low cost.Herein,we proposed a facile strategy to prepare a reduced graphene oxide/carbon fiber composite membrane,denoted as RGO/CF membrane.The surface of the RGO/CF membrane was highly hydrophobic,endowing the composite membrane with the self-floating ability on the water without any assistance.The light absorbance ability achieved as high as ca.98%in the wavelength range of 300-1200 nm.The steam evaporation efliciency under the illumination of3-sun was 97%,generating water steam at a rate of 4.54 kg·m^-2·h^-1.Moreover,the solar-thermal steam production rate showed high stability during successive 30 cvcle tests.

Kenya Airways Launches New Project to Reduce Carbon Emissions

Kenya Airways announced its new carbon offset project in May,aiming to have guests directly take part in a carbon emissions reduction plan for environmental protection.Titus Naikuni,Managing Director

Wood Companies Look to RFID to Raise Yield,Reduce Carbon Footprint

Twenty-nine European partners are developing an RFID-based application and supply-chain analysis system that may be used to increase sawmill eff iciency and raw materials usage,improve logistic operations and minimize environmental impacts.

Review of bidirectional DC–DC converter topologies for hybrid energy storage system of new energy vehicles

New energy vehicles play a positive role in reducing carbon emissions.To improve the dynamic performance and durability of vehicle powertrain,the hybrid energy storage system of“fuel cell/power battery plus super capacitor”is more used in new energy vehicles.Bidirectional DC–DC converters with wide voltage conversion range are essential for voltage matching and power decoupling between super capacitor and vehicle bus,helping to improve the low input voltage characteristics of super capacitors and realize the recovery of feedback energy.In recent years,the topologies of bidirectional converters have been widely investigated and optimized.Aiming to obtain bidirectional DC–DC converters with wide voltage conversion range suitable for hybrid energy storage system,a review of the research status of non-isolated converters based on impedance networks and isolated converters based on transformer are presented.Additionally,an evaluation system for bidirectional DC–DC topologies for hybrid energy storage system is constructed,providing a reference for designing bidirectional DC–DC converters.The performance of eight typical non-isolated converters and seven typical isolated converters are comprehensively evaluated by using this evaluation system.On this basis,issues about DC–DC converters for hybrid energy storage system are discussed,and some suggestions for the future research directions of DC–DC converters are proposed.The optimization of bidirectional DC–DC converters for hybrid energy storage system from the perspectives of wide bandgap device application,electromagnetic compatibility technology and converter fault diagnosis strategies is the main research direction.