Self-protecting CoFeAl-layered double hydroxides enable stable and efficient brine oxidation at 2 A cm-2.

Low-energy consumption seawater electrolysis at high current density is an effective way for hydrogen production, however the continuous feeding of seawater may result in the accumulation of Cl-, leading to severe anode poisoning and corrosion, thereby compromising the activity and stability. Herein, CoFeAl layered double hydroxide anodes with excellent oxygen evolution reaction activity are synthesized and delivered stable catalytic performance for 350 hours at 2 A cm-2 in the presence of 6-fold concentrated seawater. Comprehensive analysis reveals that the Al3+ ions in electrode are etched off by OH- during oxygen evolution reaction process, resulting in M3+ vacancies that boost oxygen evolution reaction activity. Additionally, the self-originated Al(OH)n- is found to adsorb on the anode surface to improve stability. An electrode assembly based on a micropore membrane and CoFeAl layered double hydroxide electrodes operates continuously for 500 hours at 1 A cm-2, demonstrating their feasibility in brine electrolysis.

Electrochemical Decarboxylative Elimination of Carboxylic Acids to Alkenes.

An electrochemical strategy for the decarboxylative elimination of carboxylic acids to alkenes at room temperature has been developed. This mild and oxidant-free method provides a green alternative to traditional thermal decarboxylation reactions. Structurally diverse aliphatic carboxylic acids, including biologically active drugs, underwent smooth conversion to the corresponding alkenes in good to excellent yields.

Ferricyanide Armed Anodes Enable Stable Water Oxidation in Saturated Saline Water at 2 A/cm2.

The direct seawater electrolysis at high current density and low overpotential affords an effective strategy toward clean and renewable hydrogen fuel production. However, the severe corrosion of anode as a result of the saturation of Cl- upon continuous seawater feeding seriously hamper the electrolytic process. Herein, cobalt ferricyanide / cobalt phosphide (CoFePBA/Co2 P) anodes with Cap/Pin structure are synthesized, which stably catalyze alkaline saturated saline water oxidation at 200-2000 mA cm-2 over hundreds of hours without corrosion. Together with the experimental findings, the molecular dynamics simulations reveal that PO4 3- and Fe(CN)6 3- generated by the electrode play synergistic role in repelling Cl- via electrostatic repulsion and dense coverage, which reduced Cl- adsorption by nearly 5-fold. The novel anionic synergy endow superior corrosion protection for the electrode, and is expected to promote the practical application of saline water electrolysis.

Electricity-Promoted Friedel-Crafts Acylation of Biarylcarboxylic Acids.

An electricity-promoted method for Friedel-Crafts acylation of biarylcarboxylic acids is described in this research. Various fluorenones can be accessed in up to 99% yields. During the acylation, electricity plays an essential role, which might motivate the chemical equilibrium by consuming the generated TFA. This study is predicted to provide an avenue to realize Friedel-Crafts acylation in a more environmentally friendly process.

Electrochemical Synthesis of Polysubstituted Oxazoles from Ketones and Acetonitrile.

Herein we report an electrochemical strategy for the construction of polysubstituted oxazoles from easily available ketones and acetonitrile under room temperature. The method shows high efficiency, a broad substrate scope, and requires no external chemical oxidant. Mechanistic investigations suggest that the reaction proceeds through a Ritter-type reaction/oxidative cyclization using acetonitrile as the reactant and solvent. X-ray crystallographic analysis reveals that the reaction involves the attack of acetonitrile on the carbonyl carbon instead of the α-carbon.

Cobalt-catalyzed synthesis of aryl ketones and aldehydes from redox-active esters.

A cobalt-catalyzed decarboxylative oxidation of benzylic redox-active esters is described. This protocol efficiently converts secondary or primary aliphatic carboxylic acids into aromatic ketones or aldehydes. A wide range of substrates selectively reacted in good to excellent yields with broad functional group tolerance. Notably, various biologically active molecules could also work well, which indicated the synthetic application of such a methodology.

Material Optimization Engineering toward xLiFePO4·yLi3V2(PO4)3 Composites in Application-Oriented Li-Ion Batteries.

The development of LiFePO4 (LFP) in high-power energy storage devices is hampered by its slow Li-ion diffusion kinetics. Constructing the composite electrode materials with vanadium substitution is a scientific endeavor to boost LFP's power capacity. Herein, a series of xLiFePO4·yLi3V2(PO4)3 (xLFP·yLVP) composites were fabricated using a simple spray-drying approach. We propose that 5LFP·LVP is the optimal choice for Li-ion battery promotion, owning to its excellent Li-ion storage capacity (material energy density of 413.6 W·h·kg-1), strong machining capability (compacted density of 1.82 g·cm-3) and lower raw material cost consumption. Furthermore, the 5LFP·LVP||LTO Li-ion pouch cell also presents prominent energy storage capability. After 300 cycles of a constant current test at 400 mA, 75% of the initial capacity (379.1 mA·h) is achieved, with around 100% of Coulombic efficiency. A capacity retention of 60.3% is displayed for the 300th cycle when discharging at 1200 mA, with the capacity fading by 0.15% per cycle. This prototype provides a valid and scientific attempt to accelerate the development of xLFP·yLVP composites in application-oriented Li-ion batteries.

Nitrogen-Doped Carbon Encapsulated Partial Zinc Stannate Nanocomposite for High-Performance Energy Storage Materials.

As a bimetal oxide, partial zinc stannate (ZnSnO3) is one of the most promising next-generation lithium anode materials, which has the advantages of low operating voltage, large theoretical capacity (1,317 mA h g-1), and low cost. However, the shortcomings of large volume expansion and poor electrical conductivity hinder its practical application. The core-shell ZnSnO3@ nitrogen-doped carbon (ZSO@NC) nanocomposite was successfully obtained by coating ZnSnO3 with polypyrrole (PPy) through in situ polymerization under ice-bath conditions. Benefiting from this unique compact structure, the shell formed by PPy cannot only effectively alleviate the volume expansion effect of ZnSnO3 but also enhance the electrical conductivity, thus, greatly improving the lithium storage performance. ZSO@NC can deliver a reversible capacity of 967 mA h g-1 at 0.1 A g-1 after 300 cycles and 365 mA h g-1 at 2 A g-1 after 1,000 cycles. This work may provide a new avenue for the synthesis of bimetal oxide with a core-shell structure for high-performance energy storage materials.

Importing Tin Nanoparticles into Biomass-Derived Silicon Oxycarbides with High-Rate Cycling Capability Based on Supercritical Fluid Technology.

Silicon oxycarbides (SiOC) are regarded as potential anode materials for lithium-ion batteries, although inferior cycling stability and rate performance greatly limit their practical applications. Herein, amorphous SiOC is synthesized from Chlorella by means of a biotemplate method based on supercritical fluid technology. On this basis, tin particles with sizes of several nanometers are introduced into the SiOC matrix through the biosorption feature of Chlorella. As lithium-ion battery anodes, SiOC and Sn@SiOC can deliver reversible capacities of 440 and 502 mAh g-1 after 300 cycles at 100 mA g-1 with great cycling stability. Furthermore, as-synthesized Sn@SiOC presents an excellent high-rate cycling capability, which exhibits a reversible capacity of 209 mAh g-1 after 800 cycles at 5000 mA g-1 ; this is 1.6 times higher than that of SiOC. Such a novel approach has significance for the preparation of high-performance SiOC-based anodes.