No abstract

No abstract

Electrocatalytic nitrogen reduction reaction (NRR) has been an important area for many scientists. However, high voltage requirements, low NH3 yield, and poor stability remain the biggest challenges for NRR. Here, novel high‐entropy alloys RuFeCoNiCu nanoparticles with small size (≈16 nm) and uniformity, prepared in oil phase at atmospheric pressure and low temperature (≤250 °C) are reported for the first time and are applied to NRR. According to the experiments, there is a high NH3 yield at a low overpotential. It has a surprising NH3 yield of 57.1 µg h–1 mgcat−1 (11.4 µg h–1 cm–2) at 0.05 V versus RHE in 0.1 m KOH, and the corresponding Faradaic efficiency reaches 38.5%, which is the electrocatalyst with the highest NH3 yield at the voltage of 0.05 V versus RHE reported so far. Similarly, the material also exhibits excellent electrochemical properties in other electrolytes such as 0.1 m Li2SO4, 0.1 m Na2SO4, and 0.1 m HCl electrolytes. Besides, after the 100 h test, only slightly diminished in activity. Theoretical calculation shows that Fe surrounded by alloy metals is the best site for N2 adsorption and activation. Co‐Cu and Ni‐Ru couples show an excellent capacity to surface hydrogenation at a low overpotential.

No abstract

Although intensive efforts have been made and great progress has been achieved relating to the electrocatalytic hydrogen evolution reaction (HER), an advanced synthesis strategy for an efficient electrocatalyst is still the most significant goal.

SUMMARYAn experimental setup was constructed to record the real-time mass data of eight pure polymers under the UL94 vertical burning test conditions. The experiments showed that the flame rises up to the clamp or the dripping occurs soon for the pure polymers. The mass burned before the flame reaching the clamp and the dripping occurrence only accounts for a small fraction of the original mass of the specimen, which differentiates the UL94 test from the cone calorimeter test. The mass loss rate of polymer specimens is in the magnitude order of 0.001-0.01 g/s. It was also found that the flame of thin specimens usually reaches the clamp sooner than that of thick specimens. Apart from the dripping behaviors found in large-scale fires, it is found that the diameter of the first drop for the tested polymers is in the range of 2.0-10.0 mm. The mass of the first drop increases with the first dripping time. The first dripping time and the mass of the first drop increase with the thickness of the specimen, especially for polymers of large-size dripping type.

No abstract

No abstract