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Graphene oxide encapsulated by mesoporous silica for intelligent anticorrosive coating: studies on release models and self-healing ability (vol 48, pg 13064, 2019)
No full textAtmospheric Hygroscopic Ionogels with Dynamically Stable Cooling Interfaces Enable a Durable Thermoelectric Performance Enhancement
No full textIn thermoelectric generator (TEG) systems, heat dissipation from their cold sides is an accessible, low-cost, and effective way to increase the temperature gap for their thermoelectric performance enhancement. Although significant efforts have been dedicated mediated by hygroscopic hydrogel coolers as self-sustained alternatives for effective heat removal, it still remains a challenge for overcoming instabilities in their cooling process. The inevitable mechanical deformation of these conventional hydrogels induced by excessive water desorption may cause a detached cooling interface with the targeted substrates, leading to undesirable cooling failure. Herein, a self-sustained and durable evaporative cooling approach for TEG enabled by atmospheric hygroscopic ionogels (RIGs) with stable interfaces to efficiently improve its thermoelectric performance is proposed. Owing to its superior hygroscopicity, the RIGs can achieve higher heat dissipation for TEG through water evaporation than that of common commercial metal heat sinks. Moreover, its favorable adhesion enables the RIG closely interact with the TEG surface either in static or dynamic conditions for a durable thermoelectric performance enhancement. It is believed that such a self-sustained evaporative cooling strategy based on the RIG will have great implications for the enhancement of TEG's efficiency, demonstrating a great promise in intermittent thermal-energy utilizations
Stepwise Assembly of a Multicomponent Heterometallic Metal-Organic Framework via Th-6-Based Metalloligands
No full textHerein we present a new metalloligand, Th6L12 [IHEP-10; L = 4-pyrazolecarboxylic acid (H2PyC)], which can be used to generate a novel multicomponent heterometallic metal-organic framework (MOF), [[Cu-3(mu(3)-OH)(NO3)(H2O)(2)](2)Th-6(mu O-3)(4)(mu(3)-OH)(4)(PyC)(6)(HPyC)(6)(H2O)(6)](NO3)(2) (IHEP-11), through further assembly with second [Cu3(mu 3-OH)(PyC)3] clusters. In IHEP-11, six Cu-3 clusters are connected by six NO3- anions to form an unprecedented annular Cu-18 cluster, which can be viewed as a 12-connected node to link with 12 Th-6 clusters, resulting a 4,12-connected shp net. Benefiting from the cationic framework and 3D porous structure, IHEP-11 can efficiently remove ReO4- (an analogue of radioactive (TcO4-)-Tc-99) from aqueous solution in a wide pH range. This work highlights the feasibility of constructing multicomponent MOFs through a step-by-step synthesis strategy based on metalloligands
Multilayer architecture design to enhance load-bearing capacity and tribological behavior of CrAlN coatings in seawater
No full textSteel materials employed in severe conditions including strong corrosion, high load and multi-factor coupling damages can easily cause incredible degradation until failure, and the protective CrN-based coatings should be one of promising candidates to relieve those damages for the steel equipment or components. In present paper, the monolayer CrAlN and multilayer Cr/CrAlN coatings were successfully deposited on steel substrates by multi arc ion technology, and their microstructure, mechanical, tribological and corrosion performances were systematically investigated. The results show that the special multilayer Cr/CrAlN coating could possess much better load-bearing capacity and wear resistance than that of monolayer CrAlN coating, which was due to the facts that the multilayer architecture can effectively release the internal stress and inhibit the expansion of defects. Particularly, the multilayer interfaces could effectively prevent the aggressive medium in seawater infiltrating into the inside of coating, and thus the multilayer Cr/CrAlN coating could have higher corrosion resistance compared to monolayer CrAlN coating. As a result, this multilayer Cr/CrAlN coating could achieve excellent combined performances, indicating that it has greatly potential application as protective coating in seawater
Harnessing the Volume Expansion of MoS3 Anode by Structure Engineering to Achieve High Performance Beyond Lithium-Based Rechargeable Batteries
No full textBeyond-lithium-ion storage devices are promising alternatives to lithium-ion storage devices for low-cost and large-scale applications. Nowadays, the most of high-capacity electrodes are crystal materials. However, these crystal materials with intrinsic anisotropy feature generally suffer from lattice strain and structure pulverization during the electrochemical process. Herein, a 2D heterostructure of amorphous molybdenum sulfide (MoS3) on reduced graphene surface (denoted as MoS3-on-rGO), which exhibits low strain and fast reaction kinetics for beyond-lithium-ions (Na+, K+, Zn2+) storage is demonstrated. Benefiting from the low volume expansion and small sodiation strain of the MoS3-on-rGO, it displays ultralong cycling performance of 40 000 cycles at 10 A g(-1) for sodium-ion batteries. Furthermore, the as-constructed 2D heterostructure also delivers superior electrochemical performance when used in Na+ full batteries, solid-state sodium batteries, K+ batteries, Zn2+ batteries and hybrid supercapacitors, demonstrating its excellent application prospect
Recent Progress toward Ab Initio Modeling of Electrocatalysis
No full textElectrode potential is the key factor for controlling electrocatalytic reactions at electrochemical interfaces, and moreover, it is also known that the pH and solutes (e.g., cations) of the solution have prominent effects on electrocatalysis. Understanding these effects requires microscopic information on the electrochemical interfaces, in which theoretical simulations can play an important role. This Perspective summarizes the recent progress in method development for modeling electrochemical interfaces, including different methods for describing the electrolytes at the interfaces and different schemes for charging up the electrode surfaces. In the final section, we provide an outlook for future development in modeling methods and their applications to electrocatalysis
Improving performance of laser and shaped tube electrochemical machining by using retracted hybrid tubular tool electrode
No full textThe coaxial laser has been introduced to shaped tube electrochemical machining (STEM), referred to as laser-STEM, to enhance the materials removal rate and precision. To address the issue of central residual formation during the laser-STEM process, which limited the machining stability and feeding rate, the retracted hybrid tubular electrode was applied. The formation mechanisms and effects of the W-shaped central residual were analyzed. Simulation and experiments were conducted to study the impact of the retracted length of the tubular electrode. Simulation results showed that a retracted length of 1-1.5 mm of the inner low-refractive layer could improve the electric current density distribution homogeneity to remove the W-shaped central residual in the machining area. The electric current density distribution homogeneity in the machining zone has been decreased by 38% by utilizing the hybrid tubular electrode with a retracted length of 2.0 mm. With a proper retracted length, the laser coupling efficiency exceeded 74.5%. Hence, the retracted hybrid tubular electrode could act as both the tool electrode and optical waveguide in the laser-STEM process. Experimental results proved that the machining efficiency and precision of laser-STEM could be enhanced by utilizing the retracted hybrid tubular electrode. With the retracted length deg rising from 0 to 1.5 mm, the maximum feeding speed increased by 373%, and the machining precision was improved by 42.2%. The maximum feeding rate of 4.1 mm/min has been achieved using the retracted hybrid tubular electrode in the laser-STEM process, which has been improved by 105%, compared with the available maximum feeding rate of the tubular electrode in the STEM process. Finally, the small holes with a diameter of 1.4 mm and an aspect ratio of 15 have been processed by laser-STEM with the retracted hybrid tubular electrode
Nanoscale Near-Field Steering of Magnetic Vortices
No full textThe utility of local fields formed around a biased conductive scanning nanoscale tip is demonstrated for the trapping, tracking, and displacement of magnetic textures hosted by a substrate. The method operates at a low energy cost, is noninvasive, and is highly controllable. Detailed results are presented for the dynamic of a magnetic vortex in the sample beneath the tip. It is shown that the near-field-assisted tracking does not suffer from the usually undesirable transversal motion of magnetic vortices or skyrmions due to the topological Hall effect. Tuning the near field of the tip allows for the generation of packaged skyrmions with different topological charges. The results endorse the potential of near-field engineering for information storage and processing based on topological magnetic structure
Efficient Fenton-Like Catalysis Boosting the Antifouling Performance of the Heterostructured Membranes Fabricated via Vapor-Induced Phase Separation and In Situ Mineralization
No full textA photocatalytic membrane with significant degradation and antifouling performance has become an important part in wastewater treatment. However, the low catalyst loading on the polymer membrane limits its performance improvement. Herein, we fabricated poly(vinylidene fluoride) (PVDF) and poly(acrylic acid) (PAA) blend membranes with a rough surface via a vapor-induced phase separation (VIPS) process. Then Fe3+ was cross-linked with the carboxyl groups on the membrane surface and further in situ mineralized into beta-FeOOH nanorods. The resultant membranes exhibit not only hydrophilicity and underwater superoleophobicity but also favorable separation efficiency and high water flux in oil-in-water emulsions separation. Under visible light irradiation, the membrane can degrade methylene blue (MB) to 95.2% in 180 min. More importantly, the membrane has a significant photocatalytic self-cleaning ability for crude oil with a flux recovery ratio (FRR) as high as 94.1%. This work brings a new strategy to fabricate the rough and porous surface for high loading of the hydrophilic photo-Fenton catalyst, improving the oil/water emulsion separation and antifouling performance of the membranes
Study of Ag-Sb coatings prepared by non-cyanide electrodeposition
No full textIn order to improve the wear resistance and corrosion resistance of silver coating under electrical contact friction environment, Ag-Sb coatings have been prepared via a non-cyanide electrodeposition process. The surface morphology, microstructure, microhardness, wear resistance, corrosion resistance and electrical resistivity of Ag-Sb coatings have been studied and the effect of Sb content has been discussed. The non-cyanide electro-deposited Ag-Sb coatings have a flatter and more compact surface morphology by comparison with the non-cyanide electrodeposited Ag coating due to the addition of KSbOC4H4O6 as Ag-plating brightener. The Ag-2Sb coating prepared from the bath containing 3 g.L-1 KSbOC4H4O6 obtains the highest microhardness of 146.5 HV and best wear resistance. The electrochemical testing results show a corrosion current density of Ag-Sb coatings range from 1.14 x 10(-5) A.cm(-2) to 4.20 x 10(-7) A.cm(-2) whereas the Ag-2Sb coating achieves the best corrosion resistance