Nowadays, the state-of-the-art electrocatalysts for hydrogen evolution reaction (HER) are platinum group metals. Nonetheless, Pt-based catalysts show decreased HER activity in alkaline media compared with that in acidic media due to the sluggish dissociation process of H O on the surface of Pt. With a cost 1/25 that of Pt, Ru demonstrates a favorable dissociation kinetics of absorbed H O. Herein, crystalline Ru Se nanoparticles are decorated onto TiO nanotube arrays (TNAs) to fabricate Ru Se @ TNA hybrid for HER. Owing to the large-specific surface area, Ru Se nanoparticles are freely distributed and the particle aggregation is eliminated, providing more active sites. The contracted electron transport pathway rendered by TiO nanotubes and the synergistic effect at the interface significantly improve the charge transfer efficiency in the hybrid catalyst. Compared with Ru Se nanoparticles deposited directly on the Ti foil (Ru Se/Ti) or carbon cloth (Ru Se/CC), Ru Se @ TNA shows an enhanced catalytic activity with an overpotential of 57 mV to afford a current density of 10 mA cm , a Tafel slope of 50.0 mV dec . Furthermore, the hybrid catalyst also exhibits an outstanding catalytic stability. The strategy here opens up a new synthetic avenue to the design of highly efficient hybrid electrocatalysts for hydrogen production.

Moore's law predicts the performance of integrated circuit doubles every two years, lasting for more than five decades. However, the improvements of the performance of energy density in batteries lag far behind that. In addition, the poor flexibility, insufficient-energy density, and complexity of incorporation into wearable electronics remain considerable challenges for current battery technology. Herein, a lithium-ion cable battery is invented, which is insensitive to deformation due to its use of carbon nanotube (CNT) woven macrofilms as the charge collectors. An ultrahigh-tap density of 10 mg cm of the electrodes can be obtained, which leads to an extremely high-energy density of 215 mWh cm . The value is approximately seven times than that of the highest performance reported previously. In addition, the battery displays very stable rate performance and lower internal resistance than conventional lithium-ion batteries using metal charge collectors. Moreover, it demonstrates excellent convenience for connecting electronics as a new strategy is applied, in which both electrodes can be integrated into one end by a CNT macrorope. Such an ultrahigh-energy density lithium-ion cable battery provides a feasible way to power wearable electronics with commercial viability.

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Gallium (indium)-containing dust as a hazardous waste generated from light-emitting diode (LED) epitaxial wafer manufacturing attracts worldwide attention because of both resources and environmental importance. Oxidative roasting combined with acidic leaching is frequently utilized to recover the corresponding metals from such dust, while the recovery rate is usually low because of the rather inert physicochemical properties of gallium compounds. Simultaneously, the selectivity of leaching is low, which results in complex separation or purification is required in order to obtain the required product (e.g., metallic gallium, Ga­(OH)3). In this research, it is demonstrated that the selectivity of leaching can be achieved via properly controlling the physicochemical properties of the leaching solution and the leaching conditions. The leaching rate of gallium can reach 90.01% through optimizing the effects of different parameters, including leaching reagent concentration, solid-to-liquid ratio, reaction temperature, reaction time, and rotation rate, which is about 16% higher than the conventional method. Moreover, the corresponding leaching mechanisms and kinetics were also evaluated, and the apparent activation energy of the reaction is determined as 24.33 kJ/mol. Without further purification, 99.8% of gallium and 99.1% of indium can be further recovered as Ga­(OH)3 and In­(OH)3 from the leaching solutions, respectively. In the whole process, the effective recycling rates of gallium and indium are 89.83% and 92.42%, respectively. This study provides bases for developing an effective recycling process of such waste with high recovery rate, advanced selectivity, and low environmental impacts.

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