Development of covalent-organic frameworks derived hierarchical porous hollow carbon spheres based LiOH composites for thermochemical heat storage

Under the joint assistance of its excellent storage strength, accessible long storage lifespan, and high heat utilization efficiency, salt hydrate-based thermochemical heat storage(THS) materials give renewable energy an important outlet to alleviate the pressure of underutilization. Herein, an activated hollow spherical carbon(AHSC) with hierarchical porous architectures converted from covalent-organic frameworks(COFs) is constructed and utilized as the supporting matrix for Li OH.THS composite material for the first time. The obtained Li/AHSC_(3) composites have distinguished hydration performance while manifesting impressive storage ability up to 1916.4 k J kg^(-1)with low operating temperature stemming from the collective effect of the void spherical framework, multimodal porosity, and high surface area of AHSC3. And the Li/AHSC3-40 composite with evidently progressed thermal conductivity is capable of realizing 94.5% heat preservation after twenty-five adsorption-desorption cycles, exhibiting its eminent cyclability and great heat transfer performance. This study not only brings new hope for overcoming the underutilization of low-grade heat but also may enlighten new ideas for enriching the application scenarios of COFs-derived carbonaceous materials.

A splice site mutation in the FvePHP gene is associated with leaf development and f lowering time in woodland strawberry

Leaves and f lowers are crucial for the growth and development of higher plants.In this study we identified a mutant with narrow leaf lets and early f lowering(nlef)in an ethyl methanesulfonate-mutagenized population of woodland strawberry(Fragaria vesca)and aimed to identify the candidate gene.Genetic analysis revealed that a single recessive gene,nlef,controlled the mutant phenotype.We found that FvH4_1g25470,which encodes a putative DNA polymeraseαwith a polymerase and histidinol phosphatase domain(PHP),might be the candidate gene,using bulked segregant analysis with whole-genome sequencing,molecular markers,and cloning analyses.A splice donor site mutation(C to T)at the 5-end of the second intron led to an erroneous splice event that reduced the expression level of the full-length transcript of FvePHP in mutant plants.FvePHP was localized in the nucleus and was highly expressed in leaves.Silencing of FvePHP using the virus-induced gene silencing method resulted in partial developmental defects in strawberry leaves.Overexpression of the FvePHP gene can largely restore the mutant phenotype.The expression levels of FveSEP1,FveSEP3,FveAP1,FveFUL,and FveFT were higher in the mutants than those in‘Yellow Wonder’plants,probably contributing to the early f lowering phenotype in mutant plants.Our results indicate that mutation in FvePHP is associated with multiple developmental pathways.These results aid in understanding the role of DNA polymerase in strawberry development.

Influence of pore structure on biologically activated carbon performance and biofilm microbial characteristics

Optimizing the characteristics of granular activated carbon(GAC)can improve the performance of biologically activated carbon(BAC)filters,and iodine value has always been the principal index for GAC selection.However,in this study,among three types of GAC treating the same humic acidcontaminated water,one had an iodine value 35%lower than the other two,but the dissolved organic carbon removal efficiency of its BAC was less than 5%away from the others.Iodine value was found to influence the removal of different organic fractions instead of the total removal efficiency.Based on the removal and biological characteristics,two possible mechanisms of organic matter removal during steady-state were suggested.For GAC with poor micropore volume and iodine value,high molecular weight substances(3500–9000 Da)were removed mainly through degradation by microorganisms,and the biodegraded organics(soluble microbial by-products,<3500 Da)were released because of the low adsorption capacity of activated carbon.For GAC with higher micropore volume and iodine value,organics with low molecular weight(<3500 Da)were more easily removed,first being adsorbed by micropores and then biodegraded by the biofilm.The biomass was determined by the pore volume with pore diameters greater than 100μm,but did not correspond to the removal efficiency.Nevertheless,the microbial community structure was coordinate with both the pore structure and the organic removal characteristics.The findings provide a theoretical basis for selecting GAC for the BAC process based on its pore structure.

Fabrication of LiOH-metal organic framework derived hierarchical porous host carbon matrix composites for seasonal thermochemical energy storage

By virtue of its long lifespan and outstanding storage intensity with near-zero heat loss,salt hydrate thermochemical energy storage(TES)materials provide a feasible option for the effective use of renewable energy and overcoming its unsynchronized supply and demand.Here,an activated porous carbon originating from the zeolite imidazolate framework(ZHCM)is fabricated and served as the carbon matrix for the LiOH TES material.The as-synthesized Li/ZHCM2-40 not only has excellent storage intensity(maximum 2414.2 kJ·kg^(−1))with low charging temperature,but also shows great hydration properties stemming from the ultrahigh surface area and hierarchical porous structure of ZHCM2.Besides,this composite material exhibits superior thermal conductivity,while its storage intensity is only attenuated by 10.2%after 15 times of consecutive charge-discharge process,revealing its outstanding cycle stability.And the numerical simulation results also demonstrate its superior heat transfer performance.The developed LiOH TES composite may afford a new avenue for efficient low-grade thermochemical energy storage and liberate the possibility of further exploration of metal organic frameworks derived porous carbon matrix in the future.

Regulating bifunctional flower-like NiFe_(2)O_(4)/graphene for green EMI shielding and lithium ion storage

Environment and energy are the eternal hot topics in the world,multiloculated microscale materials have attracted great attention in the field of electromagnetic interference(EMI)shielding and lithium ions storage.Herein,a novel flower-like NiFe_(2)O_(4)/graphene composite with adjustable structure was fabricated as EMI shielding material and anode material of lithium-ion batteries.NiFe_(2)O_(4)/graphene composite is a potential green EMI shielding material.The EMI shielding effectiveness(SE)increases with the increase of graphene content in NiFe_(2)O_(4)/graphene composite,and the total EMI SE of NiFe_(2)O_(4)/graphene with 73.6 wt.%graphene increases from 26.5 to 40.6 d B with the increase of frequency in 2–18 GHz.Furthermore,it exhibits long-life and large capacity lithium storage performance at high current density.The capacity reaches 732.79 m Ah g^(-1)after 100 cycles at 0.1 A g^(-1),recovering to more than 139%from the minimum capacity value.After 300 cycles at 0.5 A g^(-1),the capacity increases to 688.5 mAh g^(-1).The initial capacities at 2 and 5 A g^(-1)are 704.9 and 717.8 mAh g^(-1),and remain 297.9 and 203.2 m Ah g^(-1)after 1000 cycles.The distinguished EMI shielding performance and electrochemical performance are mainly ascribed to the structure regulation of NiFe_(2)O_(4)/graphene composite,as well as the synergistic effect of graphene and NiFe_(2)O_(4).This research opens up infinite opportunities for the application of multifunctional and interdisciplinary materials.

A Novel Nano-sized Catalyst CeO2-CuO/Hollow ZSM-5 for NOx Reduction with NH3

Hollow-ZSM-5 was synthesized by a traditional hydrothermal method without alcohol, and a novel nano-sized Ce-Cu/hollow ZSM-5 sample was prepared by conventional incipient wetness impreganation. The catalysts were characterized by TEM, SEM, XRD, NMR and N2 adsorption-desorption. The results indicate that the hollow-ZSM-5 has a good MFI structure with large surface area. The synthesized CeO2-CuO/hollow ZSM-5 showed an excellent catalytic activity for NOx conversion（90% NOx conversion were obtained） in the temperature range of 340-550℃ under GHSV=480000 mL. g^-1.h^-1 due to its appropriate redox ability and acidity.

Sinter-resistant and high-efficient Pt/CeO2/NiAl2O4/Al2O3@SiO2 model catalysts with “composite energy traps”

The stability of nanosized catalysts at high temperature is still a challenging topic and is a crucial criterion to evaluate their suitability for industrial use. Currently, the strategy to improve the high-temperature stability of nano-sized catalysts is to restrict the migration of particles on the surface, which, however, lacks theoretical knowledge and directions. Herein, we reported a new approach that can effectively inhibit the migration and agglomeration of supported nanoparticles by fabrication of a model catalyst Pt/CeO2/NiAl2O4/Al2O3@SiO2. This catalyst is highly stable with the microstructure unchanged even after being aged at 1000 °C. Density functional theory calculations indicate that two types of confinement effects exist in the catalyst and their mechanisms were well explained from the viewpoint of "energy traps" which can also be applied to other supported catalysts.