Electrochemical reduction of CO 2 using renewable energy is a promising strategy to mitigate the CO 2 emissions and to produce valuable chemicals. However, the lack of highly selective, highly durable, and nonpreciousmetal catalysts impedes the applications of this reaction. In this work, coppernanowire-supported indium catalysts are proposed as advanced electrocatalysts for the aqueous electroreduction of CO 2 . The catalysts are synthesized by a facile method, which combines In 3+ deposition on Cu(OH) 2 nanowires, mild oxidation, and in situ electroreduction procedures. With a thin layer of metallic In deposited on the surface of the Cu nanowires, the catalyst exhibits a CO Faradaic efficiency of ∼93% at −0.6 to −0.8 V vs RHE; additionally, an unprecedented stability of 60 h is achieved. The characterization results combined with density functional theory (DFT) calculations reveal that the interface of Cu and In plays an essential role in determining the reaction pathway. The calculation results suggest that the Cu−In interface enhances the adsorption strength of *COOH, a key reaction intermediate for CO production, while destabilizes the adsorption of *H, an intermediate for H 2 evolution. We believe that these findings will provide guidance on the rational design of high-performance bimetallic catalysts for CO 2 electroreduction by creating the metal−metal interface structure.

Fabricating nanofiltration (NF) membranes with high permeating flux and simultaneous high rejection rate for desalination is rather significant and highly desired. A new avenue is reported in this work to design NF membrane by using polydopamine wrapped single-walled carbon nanotube (PD/SWCNTs) ultrathin film as support layer instead of the use of traditional polymer-based underlying layers. Thanks to the high porosity, smooth surface, and more importantly optimal hydrophilic surface of PD/SWCNTs film, a defect-free polyamide selective layer for NF membrane with thickness of as thin as 12 nm is achieved. The obtained NF membrane exhibits an extremely high performance with a permeating flux of 32 L m h bar and a rejection rate of 95.9% to divalent ions. This value is two to five times higher than the traditional NF membranes with similar rejection rate.

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Flow batteries are a promising technology for storing and discharging megawatt hours of electrical energy on the time scale of hours. The separator between the positive and negative electrodes strongly affects technical and economic performance. However, requirements for separators have not been reported in a general manner that enables quantitative evaluation of new systems such as nonaqueous flow batteries. This gap is addressed by deriving specifications for transport properties that are chemistry agnostic and align with aggressive capital cost targets. Three key transport characteristics are identified: area-specific resistance R , crossover current density i x , and the coupling between crossover and capacity loss . Suggested maximum area-specific resistances are 0.29 and 2.3 · cm 2 for aqueous and nonaqueous batteries, respectively. Allowable crossover rates are derived by considering the possible fates of active molecules that cross the separator and the coupling between Coulombic efficiency (CE) and capacity decline. The CE must exceed 99.992% when active species are unstable at the opposing electrode, while a CE of 97% can be tolerated when active molecules can be recovered from the opposing electrode. The contributions of diffusion, migration, and convection are discussed, quantified, and related to the physical properties of the separator and the active materials. Energy storage can mitigate electrical transmission bottlenecks and provide ancillary services in addition to supplying stable and continuous power when coupled to inherently variable renewable energy sources or placed in remote regions or districts with unreliable grids.1-4 Redox flow batteries (RFBs) are a class of electrochemical devices that are suitable for storing energy for multiple hours as described in several recent review articles.3,5-8 In a flow battery, the reactants or active materials are stored in external tanks separate from the reactor, enabling independent scaling of energy and power. This segregation permits cost effective implementation of electrochemical couples with low energy density. The reactants are commonly ions dissolved in an electrolyte at concentrations near 1 mol/L. A conventional battery like lead acid or lithium ion utilizing active materials with such low volumetric capacity would incur tremendous cost, mass, and volume penalties because the amount of inactive material, principally current collectors and separators, scales with volumetric capacity in enclosed architectures.9 Appropriately designed flow batteries optimize the power density of the reactor, consequently minimizing the contributions of separators and current collectors to total system cost.The primary functions of a separator are to prevent shorting of the electrodes while allowing ionic charge carriers to move freely. 10Any material that fulfills these basic functions is referred to as a separator in this work. The term membrane is reserved for a separator that selectively favors transport of a desired charge carrier, like protons, and thwart...

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The influence of cation form and degree of sulfonation on free volume, as probed via positron annihilation lifetime spectroscopy (PALS), and water and salt transport properties was determined in a systematic series of directly copolymerized disulfonated poly(arylene ether sulfone) random copolymers. Polymer samples were studied in both the dry and hydrated states. PALS-based estimates of free volume in the dry polymers were compared with those estimated using density and the Bondi group contribution method, and PALS-based free volume data for hydrated polymers were correlated with water and salt transport properties. The transport properties depend strongly on free volume cavity size. Samples with larger free volume elements have higher water and salt solubility, diffusivity, and permeability and lower water/salt diffusivity and permeability selectivity. Sorption of water alters the characteristic free volume of the polymer matrix by two competing mechanisms: water molecules partially occupy the original free volume in the initially dry polymer, thereby reducing free volume cavity size, and water swells the polymer matrix therefore increasing the mean free volume size as a result of increased polymer chain plasticization. The importance of the second effect increases as water uptake and, thus, plasticization increases.

A highly porous indium electrode was prepared with a facile electrodeposition method, which delivers remarkable activity and selectivity towards electro reduction of Co2.

Because of weak hydrophilicity, membranes always experience fouling problems during separations. This phenomenon seriously impedes the development of membrane technologies for practical industrial-oil wastewater treatment. In this work, we successfully fabricated a superhydrophilic zwitterionic poly(vinylidene fluoride) (PVDF) membrane using a two-part process with an in situ cross-linking reaction during nonsolvent-induced phase separation and a subsequent sulfonation reaction. To prepare this zwitterionic PVDF membrane, a copolymer poly(dimethylaminoethyl methacrylate-co-2-hydroxyethyl methacrylate) (PDH) was synthesized as a zwitterionic polymer precursor and used as an additive in membrane preparation. This zwitterionic additive is well-immobilized in the membrane using in situ cross-linking to ensure the long-term stability of the membrane, and subsequent sulfonation transforms the precursor to a zwitterionic polymer to produce a superhydrophilic membrane. This superhydrophilic zwitterionic PVDF membrane exhibits high water permeation flux and good antifouling properties for separating oil-in-water emulsions with high separation efficiency.