Manipulating Intermetallic Charge Transfer for Switchable External Stimulus-Enhanced Water Oxidation Electrocatalysis.

Electrocatalytic processes involving the oxygen evolution reaction (OER) present a kinetic bottleneck due to the existence of linear-scaling relationships, which bind the energies of the different intermediates in the mechanism limiting optimization. Here, we offer a way to break these scaling relationships and enhance the electrocatalytic activity of a Co-Fe Prussian blue modified electrode in OER by applying external stimuli. Improvements of ≈11 % and ≈57 % were achieved under magnetic field (0.

The role of crystal facets and disorder on photo-electrosynthesis.

Photoelectrochemistry has the potential to play a crucial role in the storage of solar energy and the realisation of a circular economy. From a chemical viewpoint, achieving high conversion efficiencies requires subtle control of the catalyst surface and its interaction with the electrolyte. Traditionally, such control has been hard to achieve in the complex multinary oxides used in PEC devices and consequently the mechanisms by which surface exposed facets influence light-driven catalysts are poorly understood.

Lowering the Water Oxidation Overpotential by Spin-Crossover in Cobalt Hexacyanoferrate.

The oxygen evolution reaction (OER) is limited by the inherent linear scaling relationships of its reaction intermediates. Manipulating the spin configuration of the water oxidation intermediates allows us to overcome these constraints. Cobalt hexacyanoferrate (CoFe-PB) is an efficient and robust water oxidation catalyst and further known as a magnetic switch.

Quasi-degenerate states and their dynamics in oxygen deficient reducible metal oxides.

The physical and chemical properties of oxides are defined by the presence of oxygen vacancies. Experimentally, non-defective structures are almost impossible to achieve due to synthetic constraints. Therefore, it is crucial to account for vacancies when evaluating the characteristics of these materials.

Versatile Nature of Oxygen Vacancies in Bismuth Vanadate Bulk and (001) Surface.

Bismuth vanadate (BiVO) has emerged as one of the most promising photoanode materials for solar fuel production. Oxygen vacancies play a pivotal role in the photoelectrochemical efficiency, yet their electronic nature and contribution to  -type conductivity are still under debate. Using first-principles calculations, we show that oxygen vacancies in BiVO have two distinguishable geometric configurations characterized by either undercoordinated, reduced VO and BiO subunits or a V-O-V bridge (split vacancy), quenching the oxygen vacancy site.

Comparative Study of Wall-Shear Stress at the Ascending Aorta for Different Mechanical Heart Valve Prostheses.

An experimental study is reported which investigates the wall shear stress (WSS) distribution in a transparent model of the human aorta comparing an St. Jude Medical (SJM) Regent bileaflet mechanical heart valve (BMHV) with the Lapeyre-Triflo FURTIVA trileaflet mechanical heart valve (TMHV) in physiological pulsatile flow. Elastic microcantilever structures, calibrated as micropillar WSS sensors by microparticle-image-velocimetry measurements, are applied to the wall along the ascending aorta (AAo).

Cobalt Hexacyanoferrate on BiVO Photoanodes for Robust Water Splitting.

The efficient integration of photoactive and catalytic materials is key to promoting photoelectrochemical water splitting as a sustainable energy technology built on solar power. Here, we report highly stable water splitting photoanodes from BiVO photoactive cores decorated with CoFe Prussian blue-type electrocatalysts (CoFe-PB). This combination decreases the onset potential of BiVO by ∼0.

Level Alignment as Descriptor for Semiconductor/Catalyst Systems in Water Splitting: The Case of Hematite/Cobalt Hexacyanoferrate Photoanodes.

The realization of artificial photosynthesis may depend on the efficient integration of photoactive semiconductors and catalysts to promote photoelectrochemical water splitting. Many efforts are currently devoted to the processing of multicomponent anodes and cathodes in the search for appropriate synergy between light absorbers and active catalysts. No single material appears to combine both features.

A Database of the Structural and Electronic Properties of Prussian Blue, Prussian White, and Berlin Green Compounds through Density Functional Theory.

Prussian blue and its related compounds are formed by cheap and abundant metals and have shown their importance in the generation of new fuels by renewable sources. To optimize these compounds it is important to understand their electronic structure and thus establish robust structure-activity relationships. To this end, we employed theoretical simulations based on density functional theory, employing functionals of different degree of complexity, including pure generalized gradient approximation (GGA) and GGA+U functionals, which introduce self-interaction correction terms through the Hubbard parameter, and compared those to the hybrid functionals HSE03 and HSE06.

Vortex formation with a snapping shrimp claw.

Snapping shrimp use one oversized claw to generate a cavitating high speed water jet for hunting, defence and communication. This work is an experimental investigation about the jet generation. Snapping shrimp (Alpheus-bellulus) were investigated by using an enlarged transparent model reproducing the closure of the snapper claw.

Dynamic nuclear polarization NMR spectroscopy of microcrystalline solids.

Dynamic nuclear polarization (DNP) solid-state NMR has been applied to powdered microcrystalline solids to obtain sensitivity enhancements on the order of 100. Glucose, sulfathiazole, and paracetamol were impregnated with bis-nitroxide biradical (bis-cyclohexyl-TEMPO-bisketal, bCTbK) solutions of organic solvents. The organic solvents were carefully chosen to be nonsolvents for the compounds, so that DNP-enhanced solid-state NMR spectra of the unaltered solids could be acquired.