Bi-Functional Co/Al Modified 1T-MoS2 /rGO Catalyst for Enhanced Uranium Extraction and Hydrogen Evolution Reaction in Seawater.

Uranium is a key element in the preparation of nuclear fuel. An electrochemical uranium extraction technique is proposed to achieve high efficiency uranium extraction performance through HER catalyst. However, it is still a challenge to design and develop a high-performance hydrogen evolution reaction (HER) catalyst for rapid extraction and recovery of uranium from seawater. Herein, a bi-functional Co, Al modified 1T-MoS2 /reduced graphene oxide (CA-1T-MoS2 /rGO) catalyst, showing a good HER performance with a HER overpotential of 466 mV at 10 mA cm-2 in simulated seawater, is first developed. Benefiting from the high HER performance of CA-1T-MoS2 /rGO, efficient uranium extraction is achieved with a uranium extraction capacity of 1990 mg g-1 in simulated seawater without post-treatment, exhibiting a good reusability. The results of experiments and density functional theory (DFT) show that a high uranium extraction and recovery capability is attributed to the synergy effect of the improved HER performance and the strong adsorption capacity between U and OH*. This work provides a new strategy for the design and preparation of bi-functional catalysts with high HER performance and uranium extraction and recovery capabilities in seawater.

Lithium Ferrocyanide Catholyte for High-Energy and Low-cost Aqueous Redox Flow Batteries.

Aqueous redox flow batteries (ARFBs) are a promising technology for grid-scale energy storage, however, their commercial success relies on redox-active materials (RAM) with high electron storage capacity and cost competitiveness. Herein, a redox-active material lithium ferrocyanide (Li4 [Fe(CN)6 ]) is designed. Li+ ions not only greatly boost the solubility of [Fe(CN)6 ]4- to 2.32 M at room temperature due to weak intermolecular interactions, but also improves the electrochemical performance of [Fe(CN)6 ]4-/3- . By coupling with Zn, ZIRFBs were built, and the capacity of the batteries was as high as 61.64 Ah L-1 (pH-neutral) and 56.28 Ah L-1 (alkaline) at a [Fe(CN)6 ]4- concentration of 2.30 M and 2.10 M. These represent unprecedentedly high [Fe(CN)6 ]4- concentrations and battery energy densities reported to date. Moreover, benefiting from the low cost of Li4 [Fe(CN)6 ], the overall chemical cost of alkaline ZIRFB is as low as $11 per kWh, which is one-twentieth that of the state-of-the-art VFB ($211.54 per kWh). This work breaks through the limitations of traditional electrolyte composition optimization and will strongly promote the development of economical [Fe(CN)6 ]4-/3- -based RFBs in the future.

Optically Induced Molecular Logic Operations.

Molecular electronics is a promising route for down-sizing electronic devices. Tip-enhanced Raman spectroscopy provides us a setup to probe current-driven molecular junctions that are considered as prototypes of molecular electronic devices. In this setup, the plasmonic tip concentrates optical fields to a degree that allows observing optical response of single molecules. Simultaneously, the tip can also induce a localized optical angular momentum, which has been seldomly considered in previous studies. Here, we propose that the induced optical angular momentum can interact with the probed molecule and strongly modify the response signal. Specifically, we demonstrate the ability to control the vibrational resonance of current-driven molecular junctions with the optical angular momentum. This precise control of light-matter interactions at the nanoscale allows us to demonstrate multiple logic operations. These results provide a fundamental understanding of future molecular electronics applications.

Chemical grafting of Co9S8 onto C60 for hydrogen spillover and storage.

Metal modified C60 is considered to be a potential hydrogen storage medium due to its high theoretical capacity. Research interest is growing in various hybrid inorganic compounds-C60. While the design and synthesis of a novel hybrid inorganic compound-C60 is difficult to attain, it has been theorized that the atomic hydrogen could transfer from the inorganic compound to the adjacent C60 surfaces via spillover and surface diffusion. Here, as a proof of concept experiment, we graft Co9S8 onto C60via a facile high energy ball milling process. The Raman, XPS, XRD, TEM, HTEM and EELS measurements have been conducted to evaluate the composition and structure of the pizza-like hybrid material. In addition, the electrochemical measurements and calculated results demonstrate that the chemical "bridges" (C-S bonds) between these two materials enhance the binding strength and, hence, facilitate the hydriding reaction of C60 during the hydrogen storage process. As a result, an increased hydrogen storage capacity of 4.03 wt% is achieved, along with a favorable cycling stability of ∼80% after 50 cycles. Excluding the direct hydrogen storage contribution from Co9S8 in the hybrid paper, the hydrogen storage ability of C60 was enhanced by 5.9× through the hydriding reaction caused by the Co9S8 modifier. Based on these experimental measurements and theoretical calculations, the unique chemical structure reported here could potentially inspire other C60-based advanced hybrids.

Hydrogen storage in a chemical bond stabilized Co9S8-graphene layered structure.

With the high energy ball milling method, a Co9S8-decorated reduced graphene oxide (RGO) composite, which shows excellent hydrogen storage capacity, has been successfully fabricated with a well-organized layered structure. Moreover, the stabilized mechanism of the well-organized layered structure is investigated and attributed to the strong interactions between Co9S8 and defective RGO. The C-S bond interaction is identified and the hydrogen storage process is also studied with different analysis methods. Finally, an optimized Co9S8 to RGO weight ratio of 6:1 shows excellent electrochemical performances in terms of the excellent cycling stability and competitive hydrogen storage capacity of 4.86 wt%.