Fabrication of zinc-loaded hollow glass microspheres (HGMs) for hydrogen storage

Abstract

The greatest challenge for a feasible hydrogen economy lies on the production of pure hydrogen and the materials for its storage with controlled release at ambient conditions. Hydrogen with its great abundance, high energy density and clean exhaust is a promising candidate to meet the current global challenges of fossil fuel depletion and green house gases emissions. Extensive research on hollow glass microspheres (HGMs) for hydrogen storage is being carried out world-wide, but the right material for hydrogen storage is yet underway. But many other characteristics, such as the poor thermal conductivity etc. of the HGMs, restrict the hydrogen storage capacity. In this work, we have attempted to increase the thermal conductivity of HGMs by ZnO doping. The HGMs with Zn weight percentage from 0 to 10 were prepared by flame spheroidization of amber-colored glass powder impregnated with the required amount of zinc acetate. The prepared HGMs samples were characterized using field emission-scanning electron microscope (FE-SEM), environmental SEM (ESEM), high-resolution transmission electron microscopy (HRTEM), Fourier transform infrared spectroscopy and X-ray diffraction (XRD) techniques. The deposition of ZnO on the microsphere walls was observed using FE-SEM, ESEM and HRTEM which was further confirmed using the XRD and ultraviolet-visible absorption data. The hydrogen storage studies done on these samples at 200°C and 10-bar pressure for 5 h showed that the hydrogen storage increased when the Zn percentage in the sample increased from 0 to 2%. The percentage of zinc beyond 2, in the microspheres, showed a decline in the hydrogen storage capacity. The closure of the nanopores due to the ZnO nanocrystal deposition on the microsphere surface reduced the hydrogen storage capacity. The hydrogen storage capacity of HAZn2 was found 3.26 wt% for 10-bar pressure at 200°C.

Cr/S/TiO2-loaded hollow glass microspheres as an efficient and recyclable catalyst for the photocatalytic degradation of indigo carmine under visible light

“…[13][14][15][16] Hollow glass microspheres (HGM) are widely used in various fields. [17][18][19] HGM-TiO 2 is an important composite material and became commercially available. It is easy to separate and recover.…”

Advancements in Solid-State Hydrogen Storage: A Review on the Glass Microspheres

“…The intriguing aspect of low thermal conductivity inherent in HGMs, a characteristic that contributes to their limited hydrogen release capacity, has sparked considerable interest among researchers. , A strategic approach to circumvent this limitation involves doping HGMs with transition metals or metal dopants. Elements such as magnesium and iron, cobalt, , and zinc have been employed to enhance the heat transfer characteristics of the microspheres, consequently amplifying their hydrogen storage capabilities.…”

“…However, excessive Zn concentrations led to pore closure and surface deposition, akin to iron and cobalt effects. An optimal 2.0 wt % Zn concentration achieved the highest hydrogen adsorption of 3.26 wt % at 200 °C and 10 bar, demonstrating that high Zn levels can aggregate, closing pores and forming surface patches, thus narrowing gap widths. , Additionally, Moosavi et al have contributed insights revealing that the porosity of alkali borosilicate glass hollow glass beads is significantly influenced by the acid leaching duration during their preparation. It was found that extending the leaching time from 30 min to 1 h led to an expansion in the pore size range from 0 to 100 to 1000 nm.…”

A hybrid hydrolytic hydrogen storage system based on catalyst-coated hollow glass microspheres

“…A thermally driven release requires temperatures of 200-400°C (473.15-673.15 K), depending on required hydrogen flow rate, sphere material and sphere dimension, and is also limited by the thermal conductivity of the spheres [26]. Another option is to utilize an infrared lamp, which has been under research since 1998 mainly but not only by the group of Shelby [20,22,24,25,27,28].…”