Designing hierarchical iron doped nickel-vanadium hydroxide microsphere as an efficient electrocatalyst for oxygen evolution reaction.

Exploring highly active and inexpensive electrocatalysts for oxygen evolution reaction (OER) is considered to be one of the preconditions for the development of energy and environment-related technologies. Nickel-based layered double hydroxides (LDHs) are extensively-studied OER electrocatalysts, but they still require relatively high overpotentials to achieve threshold current densities. In this work, iron-doped nickel-vanadium hydroxide microspheres (Fe-doped NiV HMS) were synthesized by doping iron ions into the NiV HMS through a facile cation-exchange method. The Fe-doped NiV HMS are hollow hierarchical structure stacked by high-density perpendicularly-lying nanosheets, which provide enough space for electrolyte penetration and diffusion. Owing to optimized composition and hollow hierarchical structure, the Fe-doped NiV HMS exhibits excellent electrocatalytic performance, which possessed a very low running overpotential (255 mV at 10 mA cm-2) and a smallest Tafel slope (56 mV dec-1) compared with hierarchical NiV HMS toward OER. Electrochemical results and density functional theory (DFT) manifest that Fe doping could regulate the electronic structure of NiV HMS, thus improving its electrical conductivity and electron transfer rate, and thus enhancing its catalytic activity. This research provides a convenient way to prepare Ni-based hydroxides as promising OER catalysts.

In Situ Simultaneous Cavitation-Doping Approach for Constructing Bimetallic Metal-Organic Framework Hollow Nanospheres with Enhanced Electrocatalytic Hydrogen Production.

This Communication demonstrates a novel and in situ simultaneous cavitation-doping (SCD) approach to construct bimetallic metal-doped cobalt metal-organic framework hollow nanospheres (CoM-MOF HNSs, with M = Ru or Fe). The key point of the SCD approach is the careful balance between the kinetics of Co-MOF being etched and the coordinative growth of a more stable CoM-MOF shell induced by Lewis acid (MCl3, with M = Ru or Fe). Our work provides a new method to synthesize bimetallic hollow MOFs and benefits the development of electrocatalysts.

In situ surface-derivation of AgPdMo/MoS2 nanowires for synergistic hydrogen evolution catalysis in alkaline solution.

Metallic sulfides have emerged as highly active, durable, and robust electrocatalysts for the electrocatalytic hydrogen evolution reaction (HER) due to their intriguing electronic and catalytic properties. One of the important strategies to further enhance their HER performance is to build multimetallic nanostructures by tuning the electronic state. Here we combine multimetallic structures and metal sulfides, and report an efficient strategy for the in situ surface-derivation of molybdenum sulfide nanosheets (MoS2 NSs) on Ag-Pd-Mo alloy nanowires (AgPdMo NWs) to form AgPdMo/MoS2 NWs. The heterostructure incorporates AgPdMo NWs with high conductivity and MoS2 NSs with abundant active sites, which act synergistically in alkaline solution. The as-tuned AgPdMo/MoS2 NWs exhibit Pt-like electrocatalytic performance for the HER, with a small overpotential of 54 mV at a current density of 10 mA cm-2 and a low Tafel slope of 72 mV dec-1. The present work demonstrates a potential strategy for designing heterostructures with multimetallic composition by in situ surface-derivation with enhanced performance in water splitting.

MOF-derived cobalt-nickel phosphide nanoboxes as electrocatalysts for the hydrogen evolution reaction.

The development of high-efficiency nonprecious electrocatalysts based on inexpensive and Earth abundant elements is of great significance for renewable energy technologies. Group VIII transition metal phosphides (TMPs) gradually stand out due to their intriguing properties including low resistance and superior catalytic activity and stability. Herein, we adopt a unique MOF-derived strategy to synthesize transition metal phosphide nanoboxes which can be employed as electrocatalysts for the hydrogen evolution reaction. During this process, we converted a Co-MOF to a CoNi-MOF by ion exchange and low-temperature phosphating to achieve CoNiP nanoboxes. The CoNiP nanoboxes can reach a current density of 10 mA cm-2 at a low overpotential of 138 mV with a small Tafel slope of 65 mV dec-1.

MOF-derived uniform Ni nanoparticles encapsulated in carbon nanotubes grafted on rGO nanosheets as bifunctional materials for lithium-ion batteries and hydrogen evolution reaction.

The rational-design and synthesis of transition-metal compounds with outstanding electrochemical activity and durability for renewable energy systems have attracted tremendous research interest in recent years. Herein, we report a facile and unique strategy to synthesize N-doped carbon nanotube-encapsulated Ni nanoparticles on reduced graphene oxide (Ni@NC-rGO). The optimized nanostructure determines the synergetic effects among the Ni nanoparticles, N-doped CNTs and graphene nanosheets, thus resulting in extraordinary electrochemical performances. When applied as an anode for lithium-ion batteries (LIBs), the Ni@NC-rGO electrode displayed high reversible capacity, stable cycling performance and superior rate capability. Moreover, the resulting Ni@NC-rGO nanocomposites exhibited low overpotential and considerable durability for the hydrogen evolution reaction (HER). Our study may provide a feasible methodology for the preparation of high-performance nanostructured materials for practical energy storage and conversion applications.

Photosynthetic reaction center functionalized nano-composite films: effective strategies for probing and exploiting the photo-induced electron transfer of photosensitive membrane protein.

Photosynthetic reaction center (RC), a robust transmembrane pigment-protein complex, works as the crucial component participating the primary event of the photo-electrochemical conversion in bacteria. Sparked by the high photo-induced charge separation yield (ca. 100%) of RC, great interests have been aroused to fabricate versatile RC-functionalized nano-composite films for exploring the initial photosynthetic electron transfer (ET) of RC, and thus exploiting well-designed bio-photoelectric converters. In this review, we classify and summarize the current status about the concepts and methods of constructing RC-immobilized nano-composite films or devices for probing the photo-induced ET, and applying to novel bioelectronics if it is possible.

Manipulated photocurrent generation from pigment-exchanged photosynthetic proteins adsorbed to nanostructured WO3-TiO2 electrodes.

A novel photoelectrode (PE) consisting of the pigment-exchanged photosynthetic reaction center (RC) trapped on the mesoporous WO3-TiO2 film was fabricated to facilitate bio-photoelectric conversion by manipulating the excitation relaxation of the proteins.

Effect of the in situ electrochemical oxidation on the pigment-protein arrangement and energy transfer in light-harvesting complex from Rhodobacter sphaeroides 601.

The oxidation of bacteriochlorophylls (BChls) in peripheral light-harvesting complexes (LH2) from Rhodobacter sphaeroides was investigated by spectroelectrochemistry of absorption, fluorescence emission, and femtosecond (fs) pump-probe, with the aim obtaining information about the effect of in situ electrochemical oxidation on the pigment-protein arrangement and energy transfer within LH2. The experimental results revealed that: (a) the generation of the BChl radical cation in both B800 and B850 rings dramatically induced bleaching of the characteristic absorption in the NIR region and quenching of the fluorescence emission from the B850 ring for the electrochemical oxidized LH2; (b) the BChl-B850 radical cation might act as an additional channel to compete with the unoxidized BChl-B850 molecules for rapidly releasing the excitation energy, however the B800-B850 energy transfer rate remained almost unchanged during the oxidation process.

Photoelectric performance of bacteria photosynthetic proteins entrapped on tailored mesoporous WO3-TiO2 films.

Novel three-dimensional wormlike mesoporous WO(3)-TiO(2) films with tailored pore size (approximately 7.1 nm) were applied to prepare the bio-photoelectrodes (Bio-PEs) through direct entrapping the bacteria photosynthetic reaction center (RC) proteins. These mesoporous WO(3)-TiO(2) films exhibited unique characteristics in the specific loading of RC with high activity retained. Moreover, well-matched energy levels of WO(3)-TiO(2) and RC contributed to the photoelectric performance, especially in the red to near-infrared (NIR) region, of the derived Bio-PEs. Such strategy of manipulating the Bio-PEs based on well-designed mesoporous metal oxides and RC provides an alternative system to probe the photoinduced multiple-pathway electron transfer of photosensitive chromophores, which may open a new perspective to develop versatile bio-photoelectric devices.

[Effect of the endoexpander pressure of continuous and constant pressure expansion on the drug permeability].

OBJECTIVE: To investigate the effect of the endoexpander pressure of continuous and constant pressure expansion on the drug permeability. METHODS: The expanders were divided into two groups, the normal expansion and the continuous and constant pressure expansion (4.6 kPa). Each expander was filled with 0.2% Metronidazole, then the expanders were immersed wholly in normal saline and sealed totally. At several intervals over 72 hours, the surrounding saline was sampled and the drug concentration of the sample was measured respectively. RESULTS: Both groups were permeable to the Metronidazole and the concentration outside the expander would reach the effective concentration in 48 hours. The drug concentration of the continuous and constant pressure expansion was higher than that of the normal one and there was significant difference between the two groups (P < 0.01). CONCLUSION: The endoexpander pressure in continuous and constant pressure expansion can enhance the drug permeability. In view of this, in the course of continuous and constant pressure expansion, 0.2% Metronidazole can be used to prevent and control the infection.