Chemical grafting of Co₉S₈ onto C₆₀ for hydrogen spillover and storage

Abstract

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.

Preparation and electrochemical hydrogen storage properties of Co 9 S 8 alloy coated with cobalt/graphene composite

“…This result implied the possible coexistence of metallic Co and Co 2+ in the CoRGO composite. Similar results have been reported in the previous literature 30 …”

“…Han et al have grafted Co 9 S 8 onto C 60 by the ball milling method. The strong chemical bonding of C 60 ‐Co 9 S 8 could synergistically enhance the electrochemical activity of electrode and prevent the damage of structure, which were favorable for the hydrogen transfer 30 . Co 0.9 Cu 0.1 Si alloys coated with lithium modified MWCNTs have also been prepared.…”

In Situ Formation of Co9S8 Quantum Dots in MOF‐Derived Ternary Metal Layered Double Hydroxide Nanoarrays for High‐Performance Hybrid Supercapacitors

“…Furthermore, the Raman and XPS of CF@NiCoZn‐LDH/Co 9 S 8 ‐QD at different current densities of 1, 2, 5, 10 A g −1 after 200 cycles are described in detail. According to the Raman spectra in Figure f, the characteristic peaks of Co 9 S 8 ‐QD and NiCoZn‐LDH can be clearly observed to slightly shift with the increase of current densities, which may be due to the lattice tensile strain and vibrations caused by oxygen vacancies or defects on the surface of the active materials at a higher current state . Significantly, the corresponding XPS of Co and Ni are exhibited in Figure g,h, respectively.…”

Cobalt Nanoparticles Embedded in N, S Co‐Doped Carbon towards Oxygen Reduction Reaction Derived by in situ Reducing Cobalt Sulfide

“…When the mole ratio of Co ions and sulfurs gets to 1 : 1, it might beneficial to form Co 9 S 8 phases which is stable during the pyrolysis of melamine and prevents sulfur doping into the carbon matrix. From the Figure a, there are three weak peaks at around 460 cm −1 , 515 cm −1 , 670 cm −1 corresponding to Co 9 S 8 phases existing in CoSMe‐0.25‐800, CoSMe‐0.5‐800 and CoSMe‐1‐800 samples, which means that the Co 9 S 8 phases still remain after reduction of melamine . It is contrary to the results of XRD patterns, which could be attributed to the destruction of crystalline of Co 9 S 8 during the calcination, leading to the fact that grain size of residual Co 9 S 8 is lower than detection minimum of XRD measurement or residual Co 9 S 8 are amorphous.…”