Ru/Ir-Based Electrocatalysts for Oxygen Evolution Reaction in Acidic Conditions: From Mechanisms, Optimizations to Challenges.

The generation of green hydrogen by water splitting is identified as a key strategic energy technology, and proton exchange membrane water electrolysis (PEMWE) is one of the desirable technologies for converting renewable energy sources into hydrogen. However, the harsh anode environment of PEMWE and the oxygen evolution reaction (OER) involving four-electron transfer result in a large overpotential, which limits the overall efficiency of hydrogen production, and thus efficient electrocatalysts are needed to overcome the high overpotential and slow kinetic process. In recent years, noble metal-based electrocatalysts (e.

Frontiers and Structural Engineering for Building Flexible Zinc-Air Batteries.

With the development of flexible devices, the demand for wearable power sources has increased and gradually become imperative. Zinc-air batteries (ZABs) have attracted lots of research interest due to their high theoretical energy density and excellent safety properties, which can meet the wearable energy supply requirements. Here, the flexibility of energy storage devices is discussed first, followed by the chemistries and development of flexible ZABs.

Peptide-Based Biosensing of Redox-Active Protein-Heme Complexes Indicates Novel Mechanism for Tumor Survival under Oxidative Stress.

Signal response of several relevant protein-cofactor interactions, united in one bioassay, may greatly enhance the ability to study the intriguing molecular mechanisms of pathological process such as the tumor immunological process of chronic inflammation and oxidative stress. Here, a peptide-based multiplexed bioassay has been developed and applied in studying the interactions among ferritin, p53, and heme under oxidative stress. In a malignant breast cancer cell line, it can be observed that oxidative stress-triggered nuclear co-translocations of heme and ferritin may lead to direct molecular contact of ferritin with p53, to pass heme to p53, which subsequently sequestered into the cytoplasm, therefore forming a possible new route of tumor survival under oxidative stress, by using the stress to circumvent oxidative stress-induced apoptosis.

Engineering channels of metal-organic frameworks to enhance catalytic selectivity.

This report describes a facile strategy to enhance the catalytic selectivity by tuning the pore sizes of metal-organic frameworks (MOFs) in nanoparticles (NPs)/MOF composite catalysts. A general post-synthetic modification method was used to adjust the pore sizes of MOFs by using anhydrides with different chain lengths to react with amino groups in the ligands. The modified NPs/MOF catalysts exhibited enhanced size selectivity performance in the hydrogenation of olefins, which revealed the flexibility of MOFs as supporting materials for heterogeneous catalysis.

Hierarchical Uniform Supramolecular Conjugated Spherulites with Suppression of Defect Emission.

Easily processed, well-defined, and hierarchical uniform artificial architectures with intrinsic strong crystalline emission properties are necessary for a range of light-emitting optoelectronic devices. Herein, we designed and prepared ordered supramolecular spherulites, comprising planar conformational molecules as primary structures and multiple hydrogen bonds as physical cross-links. Compared with serious aggregation-induced fluorescence quenching (up to 70%), these highly ordered architectures exhibited unique and robust crystalline emission with a high PLQY of 55%, which was much higher than those of other terfluorenes.

Fabrication of Flexible Transparent Electrode with Enhanced Conductivity from Hierarchical Metal Grids.

Flexible transparent conductive electrodes (FTCEs) are essential components for numerous optoelectronic devices. In this work, we have fabricated the hierarchical metal grids (HMG) FTCEs by a facile and low-cost, near-field photolithography strategy. Compared to normal metal grids (MG), the HMG structure can provide distinctly increased conductivity of the electrode yet without obvious reduction of the optical transmittance.

Metal-Organic Framework Wears a Protective Cover for Improved Stability.

Metal-organic frameworks (MOFs) with an ordered channel and porosity show great promise for a myriad of purposes. Unfortunately, the coordination bond of metal ions and organic ligands easily weakens in unfavorable environments, which poses a key problem in expanding the application of MOFs. Herein, we report a general and efficient strategy to enhance the stability and preserve the porosity of MOFs by coating them with reduced graphene oxide (rGO).

Multi-functional fluorescent probe for Hg2+, Cu2+ and ClO- based on a pyrimidin-4-yl phenothiazine derivative.

A multi-functional fluorescent probe based on PzDPM (10-ethyl-3,7-di(pyrimidin-4-yl)-10H-phenothiazine) for Hg(2+), Cu(2+) and ClO(-) has been synthesized and characterized. The probe comprises an electron-donating fluorophore core of 10-ethylphenothiazine and two Hg(2+)-specific chelating arms of pyrimidin-4-yl. The 10-ethylphenothiazine also acts as a Cu(2+)/ClO(-)-specific reactive moiety.

Effect of pH on the photophysical properties of two new carboxylic-substituted iridium(III) complexes.

Two cyclometalated iridium(III) complexes have been prepared based on 2-(4-diphenylamino-phenyl)-quinoline and incorporating carboxylic acid ethyl ester (–COOC(2)H(5), (TPAQCE)(2)Irpic and carboxylic acid (–COOH, (TPAQCOOH)(2)Irpic) substituents at the 4-position of the quinoline ligand, respectively. The absorption, emission and (1)H NMR spectra of (TPAQCE)(2)Irpic and (TPAQCOOH)(2)Irpic under alkaline or acidic conditions demonstrate that they respond to the pH of the surrounding solvent environment. The deprotonation of the carboxylic acid group significantly blue-shifts the metal-to-ligand charge transfer absorption band of (TPAQCOOH)(2)Irpic by 48 nm and enhances the emission quantum-yield in DMSO.

Phosphorescent chemosensor for Hg2+ and acetonitrile based on iridium(III) complex.

A new phosphorescent chemosensor for Hg(2+) and acetonitrile (MeCN) based on iridium(III) complex Ir(dpp)(2)(dtc) (Ir1, dppH = 4,6-diphenylpyrimidine, dtcH = diethyl dithiocarbamic acid) was realized. Upon addition of a tetrahydrofuran (THF) solution of Hg(2+), the dichloromethane (DCM) solution of Ir1 gave a visual color change and significant fluorescent quenching. When MeCN was added, a new fluorescent emission emerged, which constituted a selective MeCN phosphorescent chemosensor.

Theoretical studies of electron transport in thiophene dimer: effects of substituent group and heteroatom.

The electron-transport properties of various substituted molecules based on the thiol-ended thiophene dimer (2Th1DT) are investigated through density functional theory (DFT) combined with nonequilibrium Green's function (NEGF) method. The current-voltage (I-V) curves of all the Au/2Th1DT/Au systems in this work display similar steplike features, while their equilibrium conductances show a large difference and some of these I-V curves are asymmetric distinctly. The results reveal the dependence of conductance on the energy level of the substituted 2Th1DT molecules.