Currently, platinum-based electrocatalysts show the best performance for hydrogen evolution. All hydrogen evolution reaction catalysts should however obey Sabatier's principle, that is, the adsorption energy of hydrogen to the catalyst surface should be neither too high nor too low to balance between hydrogen adsorption and desorption. To overcome the limitation of this principle, here we choose a composite (rhodium/silicon nanowire) catalyst, in which hydrogen adsorption occurs on rhodium with a large adsorption energy while hydrogen evolution occurs on silicon with a small adsorption energy. We show that the composite is stable with better hydrogen evolution activity than rhodium nanoparticles and even exceeding those of commercial platinum/carbon at high overpotentials. The results reveal that silicon plays a key role in the electrocatalysis. This work may thus open the door for the design and fabrication of electrocatalysts for high-efficiency electric energy to hydrogen energy conversion.

Electrolysis of water to generate hydrogen is an important issue for the industrial production of green and sustainable energy. The best electrocatalyst currently available for the hydrogen evolution reaction (HER) is platinum. We herein show that iridium can be manipulated to achieve a record high HER activity surpassing platinum in every aspect: a lower overpotential at any given current density, a higher current density, and mass activity for all bias potentials applied and a catalyst cost reduction of 50% for the same hydrogen generation rate. The superior HER activity was achieved by a binary Ir/Si nanowire catalyst design in which (as density functional theory calculations show) two distinct strategies act in synergy: (i) decreasing the size of the iridium nanoparticles to ∼2.2 nm and (ii) dividing the H2-generation process to three steps occurring on two different catalysts: H adsorption on iridium, H diffusion to silicon, and H2 desorption from silicon.

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In this paper, pure metastable phase iron vanadate (FeVO 4 -II) ultrathin nanosheets (50 nm in thickness) with exposed {010} facets were obtained by a mild hydrothermal process, without the use of any template or organic surfactant. The photocatalytic rate of the FeVO 4 -II {010} facets was measured taking advantage of their unique morphology. Furthermore, the FeVO 4 -II catalyst could be easily separated and reused, simply by applying an external magnetic field. In addition, with their n-type semiconductor structure, FeVO 4 ultrathin nanosheets exhibited gas-sensing for an ethanol trace.

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Quantum dots (QDs) photodetectors with low cost, tunable spectral response range, the great possibility of multiple-exciton generation, and excellent detective performance have shown significant advantages in the fields of optical...

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