Enhancing Hydrogen Evolution Electrocatalytic Performance in Neutral Media via Nitrogen and Iron Phosphide Interactions

It remains a challenge to develop efficient electrocatalysts in neutral media for hydrogen evolution reaction (HER) due to the sluggish kinetics and switch of the rate determining step. Although metal phosphides are widely used HER catalysts, their structural stability is an issue due to oxidization, and the HER performance in neutral media requires improvement. Herein, a new material, i.e., grapevine-shaped N-doped iron phosphide on carbon nanotubes, as an efficient HER catalyst in neutral media is developed. The optimized catalyst shows an overpotential of 256 mV at a large current density of 65 mA cm−2, which is even 10 mV lower than that of the commercial 20% Pt/C catalyst. The excellent performance of the catalyst is further studied by combined computational and experimental techniques, which proves that the interaction between nitrogen and iron phosphides can provide more efficient active structures and stabilize the metal phosphide electrocatalysts for HER

Design of Silk-Elastin-Like Protein Nanoparticle Systems with Mucoadhesive Properties

Transmucosal drug delivery is a promising avenue to improve therapeutic efficacy through localized therapeutic administration. Drug delivery systems that increase retention in the mucosal layer are needed to improve efficiency of such transmucosal platforms. However, the applicability of such systems is often limited by the range of chemistries and properties that can be achieved. Here we present the design and implementation of silk-elastin-like proteins (SELPs) with mucoadhesive properties. SELP-based micellar-like nanoparticles provide a system to tailor chemical and physical properties through genetic engineering of the SELP sequence, which enables the fabrication of nanoparticles with specific chemical and physical features. Analysis of the adhesion of four different SELP-based nanoparticle systems in an artificial mucus system, as well as in in vitro cellular assays indicates that addition of mucoadhesive chemical features on the SELP systems increases retention of the particles in mucosal environments. The results indicated that SELP-based nanoparticles provide a useful approach to study and develop transmucosal protein drug delivery system with unique mucoadhesive properties. Future studies will serve to further expand the range of achievable properties, as well as the utilization of SELPs to fabricate mucoadhesive materials for in vivo testing

Flexible all-solid-state supercapacitors based on PPy/rGO nanocomposite on cotton fabric

Polypyrrole (PPy) has high electrochemical activity and low cost, so it has great application prospects in wearable supercapacitors. Herein, we have successfully prepared polypyrrole/reduced graphene oxide (PPy/rGO) nanocomposite cotton fabric (NCF) by chemical polymerization, which exhibits splendid electrochemical performance compared with the individual. The addition of rGO can block the deformation of PPy caused by the expansion and contraction. The as-prepared PPy-0.5/rGO NCF electrode exhibits the brilliant specific capacitance (9300 mF cm−2 at 1 mA cm−2) and the capacitance retention with 94.47% after 10 000 cycles. At the same time, the superior capacitance stability under different bending conditions and reuse capability have been achieved. All-solid-state supercapacitor has high energy density of 167 μWh cm−2 with a power density of 1.20 mW cm−2. Therefore, the PPy-0.5/rGO NCF electrode has a broad application prospect in high-performance flexible supercapacitor fabric electrode

Controlling the Recognition and Reactivity of Alkyl Ammonium Guests Using an Anion Coordination-Based Tetrahedral Cage

Caged structures have found wide application in a variety of areas, including guest encapsulation and catalysis. Although metal-based cages have dominated the field, anion-coordination-based cages are emerging as a new type of supramolecular ensemble with interesting host–guest properties. In the current work, we report a <i>C</i>₃-symmetric tris-bis­(urea) ligand based on the 2,4,6-triphenyl-1,3,5-triazine spacer, which assembles with phosphate anions to form an A₄L₄-type (A = anion, L = ligand) tetrahedral cage, <b>3</b>, with unusually high packing coefficients (up to 99.5% for the best substrate). Cage <b>3</b> is able to adjust its size and shape (from 136 to 216 ų) by bending of the triphenyltriazine plane. This allows it to accommodate relatively large guests. In the case of DABCO, inclusion within the cage allows the degree of methylation to be controlled and the monomethylated product to be isolated cleanly under conditions where mixtures of the mono- and dimethylated adduct are obtained in the absence of cage <b>3</b>