RESUMEN
Self-supported Ru-doped NiMoO4 (Ru-NiMoO4) is synthesized on commercial NiMo foam. The Ru-NiMoO4 exhibits extremely high performance for electrocatalytic hydrogen evolution with a small overpotential of 170.6 mV to afford a current density of 1000 mA cm-2, and excellent durability for 150 hours in alkaline solution.
RESUMEN
Honeycomb-like ZnFe2O4@Ni3S2 hierarchical nanosheet arrays on Ni foam (NF) were fabricated via a combined hydrothermal and electrodeposition method. The electrode exhibits high oxygen evolution reaction (OER) activity with low overpotentials of 254 mV at 10 mA cm-2 and 290 mV at 50 mA cm-2, a small Tafel slope of 39.29 mV dec-1 and excellent durability in an alkaline electrolyte.
RESUMEN
To meet the requirements for industrial water splitting to generate hydrogen, it is urgent, but still quite challenging to develop highly active and stable electrocatalysts for large-current-density hydrogen evolution reaction (HER). Herein, Ru-incorporated NiSe2 (Ru-NiSe2 ) was designed and synthesized. The introduction of Ru results in the formation of hierarchically structured Ru-NiSe2 with large electrochemical active surface area, and well-modified electronic structure. As expected, the as-fabricated Ru-NiSe2 displays impressive HER activity in 1.0â M KOH, with a low overpotential of 180.8â mV to reach the current density of 1000â mA cm-2 . Ru-NiSe2 also presents outstanding long-term stability at high current densities, owing to its high intrinsic chemical stability, and strong catalyst-support interface. Notably, when performed at a certain current density of 1000â mA cm-2 , the overpotential increase after 90â h is only 13â mV. Such excellent HER performance of Ru-NiSe2 demonstrates its great potential for practical use in industrial water splitting.
RESUMEN
The introduction of acetate in the precursor of metal-organic frameworks (MOFs) turns the final product from MOFs to NiRu/Ni(OH)2. Followed by annealing treatment, the obtained NiRu/NiO catalyst exhibits high hydrogen evolution reaction (HER) activity with a low overpotential (18 mV at 10 mA cm-2), and a small Tafel slope of 43.3 mV dec-1 in alkaline electrolyte.
RESUMEN
La2MoO6:Yb3+,Er3+ upconversion (UC) micro-crystals with a tetragonal structure were fabricated through a modified sol-gel method. The samples are found to be spherical in shape with a diameter of about 300 nm. Upon excitation of 980 nm light, the UC emission spectra of the phosphors exhibit green and red bands corresponding to the characteristic transitions of Er3+ ions. As Yb3+ concentration rises, the green emission intensity increases and reaches the maximum at 2.0% Yb3+ content, while the ratio of green/red emission intensities (IG/IR) declines monotonically. Temperature sensing capability was studied employing the fluorescent intensity ratio technique from the thermally coupled levels 2H11/2 and 4S3/2 of Er3+ in temperature range of 293â¼533 K. It is interesting to find that Yb3+ concentration has influence on the absolute sensitivity SA, while the relative sensitivity SR is almost independent of Yb3+ content. Furthermore, excellent thermal stability and high temperature sensitivity is also demonstrated in the 2.0% Yb3+-doped sample with the obtained maximum SA and SR as high as 0.008K-1 and 1.093%K-1, respectively. The experimental results indicate that Yb3+/Er3+ co-doped La2MoO6 phosphors can be excellent candidates for temperature sensing applications.
