Search

The temperature of the sample in a resistance-heated diamond anvil cell is difficult to be measured directly and usually is calibrated by reading from the thermocouple attached to the diamond bevel. It is unclear how the temperature difference between the diamond bevel and the sample is affected by external factors such as thermal radiation and air convection. We performed a finite-element method simulation of the temperature field in the resistance-heated diamond anvil cell under different external conditions, and our simulations demonstrate that a thermal insulation cover of a low emissivity material and a unique double-layer structure can effectively reduce the temperature difference. Meanwhile, there is a non-negligible difference between the sample temperature at ambient pressure and that at high pressure when the diamond bevel has the same temperature. Some results of simulations have been confirmed by experiments using a designed double-layer cover. [ABSTRACT FROM AUTHOR]

Gd 3 Ga 5 O 12 single crystals [gadolinium gallium garnet (GGG)] were shock compressed to elastic deformation, elastoplastic transformation, and structural phase-transition regimes with the corresponding single, two-wave, and three-wave structures. Velocity profiles at the front interface and the rear free surface of the sample are measured by a Doppler pin system. Results of these measurements are analyzed in detail, and the refractive index, n , at 1550 nm is obtained as a function of shock pressure or density. Incorporating previously published single-wave data above 100 GPa, characteristic variations in the refractive index are presented and discussed within the context of shock-induced polymorphism of the GGG. [ABSTRACT FROM AUTHOR]

A nontoxic FeCl3 catalyzed intramolecular oxidative coupling reaction was developed for mild synthesis of a series of phenanthrenes with different substituents. The method involves cross dehydrogenative coupling of a variety of 1,2-diarylethylene derivatives with di- tert-butylperoxide (DTBP) as a sole oxidant at room temperature in CH2Cl2/TFA (9:1 V/ V) to yield phenanthrenes in good to excellent yields. [ABSTRACT FROM AUTHOR]

Hydrogen evolution by photocatalysis shows great potential in solar energy conversion process and thus has become an active field of research. Separation efficiency of photogenerated carriers, light absorption and surface reaction are the dominant aspects that affect the photocatalytic hydrogen evolution. Creating traps to prolong the lifetime of photogenerated charge carriers has been widely used but may be considered detrimental if they lead to recombination process of the photogenerated charge carriers. Herein, we design a kind of efficient atomic substitution strategy to create shallow donor for highly efficient hydrogen evolution reaction. The photocatalytic hydrogen evolution reaction rate reaches 3766.9 μmol h−1 g−1, which is about 2.98 times higher of pure CdS. The injected foreign atoms (Zr) not only reduce bandgap to extend light absorption but also generate shallow trap level to reduce recombination of photogenerated carriers. Moreover, the introduced atoms could downshift Fermi level to supply more carriers and act the role as active center to reduce Gibbs free energy, leading to the enhanced hydrogen generation rate and superior stability. This report offers new enlightenment into designing noble-metal free photocatalysts with extraordinary catalytic performance and excellent stability. • x % Zr–CdS samples were prepared via hydrothermal method and showed enhanced photocatalytic performance. • Introduction of Zr could create shallow donor state. • Doping of Zr accelerate the transfer of electrons. • Modification of Zr reduces the energy barrier of H 2 production. [ABSTRACT FROM AUTHOR]