No abstract

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%.

Metal modified C is considered to be a potential hydrogen storage medium due to its high theoretical capacity. Research interest is growing in various hybrid inorganic compounds-C. While the design and synthesis of a novel hybrid inorganic compound-C is difficult to attain, it has been theorized that the atomic hydrogen could transfer from the inorganic compound to the adjacent C surfaces via spillover and surface diffusion. Here, as a proof of concept experiment, we graft CoS onto Cvia 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 C 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 CoS in the hybrid paper, the hydrogen storage ability of C was enhanced by 5.9× through the hydriding reaction caused by the CoS modifier. Based on these experimental measurements and theoretical calculations, the unique chemical structure reported here could potentially inspire other C-based advanced hybrids.

No abstract

Layered MoS2 with unique structural and electronic properties has received increasing research interest for its potential catalytic properties. It is a challenge to develop strategies to improve the conductivity of MoS2 nanosheets. Here, we report an aluminum decoration on MoS2 ultrathin nanosheets by using the modified atomic layer deposition technique, which shows improved conductivity and enhanced catalytic activity for hydrogen evolution reaction (HER) with overpotentials of 248 and 198 mV that are derived for Al-MoS2 at 10 mA cm–2 in acidic and basic media, respectively. The findings in this work will provide the effective way for modulating the MoS2 with the metallic decorations, which may further advance the development of the 2D material, especially for those with poor conductivity.

of uranium. [5] Therefore, research on the rapid and selective recovery of uranium element from seawater is of great impor tance for the sustainable development of the nuclear industry. [6][7][8] Currently, the common methods used to extract uranium from seawater include the adsorption, membrane separation, photocatalytic reduction, and electro chemical reduction. [9][10][11][12][13] Adsorption and membrane separation methods, as simple physical methods, have been studied a lot, but the efficiency of uranium extraction is low and more influenced by various complex factors in seawater. [14][15][16] Photo catalytic reduction is a lowcost, non polluting method but it is less efficient and requires posttreatment to separate uraniumcontaining precipitates from the electrode material after electrical extrac tion. [17][18][19] Electrochemical reduction has a high efficiency in uranium extraction. [20,21] However, posttreatment is required after electrical extraction as photocatalytic reduction. [22,23] Therefore, it is an urgent need to develop a simple and effective uranium extraction method.Recently, an electrochemical uranium extraction technique has been proposed to achieve high efficiency uranium extrac tion performance through pH changes around the electrode caused by HER. For example, Wang at al. have proved that a functionalized reduced graphene oxide foam is used as a HER catalyst material to achieve high uranium extraction perfor mance. [24] However, its HER performance is still low, leading to an insufficient uranium extraction performance, and post treatment is required after electrical extraction. Therefore, it is critical to design and develop a highperformance HER catalyst for rapid extraction and recovery of uranium from seawater. It is worth noting that MoS 2 has been widely used as HER catalyst due to its moderate hydrogen adsorption free energy. However, the practical application of MoS 2 in electrocatalysis is hindered by its weak conductivity. [25][26][27] In comparison, reduced gra phene oxide (rhas high charge mobility and large surface area, being effectively used in functional composites as an ideal sup port component. Combining MoS 2 with rGO substrates could enhance the charge transfer between MoS 2 . [28,29] At the same time, modification of various metals has also been used to improve the electrocatalytic activity in MoS 2 . [30][31][32] Compared to 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-MoS 2 /reduced graphene oxide (CA-1T-MoS 2 /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-...

No abstract

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 (Li 4 [Fe(CN) 6 ]) is designed. Li + ions not only greatly boost the solubility of [Fe(CN) 6 ] 4À to 2.32 M at room temperature due to weak intermolecular interactions, but also improves the electrochemical performance of [Fe(CN) 6 ] 4À /3À . By coupling with Zn, ZIRFBs were built, and the capacity of the batteries was as high as 61.64 Ah L À 1 (pH-neutral) and 56.28 Ah L À 1 (alkaline) at a [Fe(CN) 6 ] 4À concentration of 2.30 M and 2.10 M. These represent unprecedentedly high [Fe-(CN) 6 ] 4À concentrations and battery energy densities reported to date. Moreover, benefiting from the low cost of Li 4 [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 ] 4À /3Àbased RFBs in the future.