Exploring the capability of mayenite (12CaO\xb77Al2O3) as hydrogen storage material

Heidy Visbal,Kazuyuki Hirao,Katsuaki Suzuki,Takuya Omura,Takanori Itoh,Toru Ishigaki,Tsukuru Ohwaki,Hironori Kaji,Hideto Imai,Ayaka Maeno,Kohji Nagashima

doi:10.1038/s41598-021-85540-8

Heidy Visbal, Kazuyuki Hirao + Show 9 more

Open Access

https://doi.org/10.1038/s41598-021-85540-8

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Abstract

We utilized nanoporous mayenite (12CaO·7Al2O3), a cost-effective material, in the hydride state (H−) to explore the possibility of its use for hydrogen storage and transportation. Hydrogen desorption occurs by a simple reaction of mayenite with water, and the nanocage structure transforms into a calcium aluminate hydrate. This reaction enables easy desorption of H− ions trapped in the structure, which could allow the use of this material in future portable applications. Additionally, this material is 100% recyclable because the cage structure can be recovered by heat treatment after hydrogen desorption. The presence of hydrogen molecules as H− ions was confirmed by 1H-NMR, gas chromatography, and neutron diffraction analyses. We confirmed the hydrogen state stability inside the mayenite cage by the first-principles calculations to understand the adsorption mechanism and storage capacity and to provide a key for the use of mayenite as a portable hydrogen storage material. Further, we succeeded in introducing H− directly from OH− by a simple process compared with previous studies that used long treatment durations and required careful control of humidity and oxygen gas to form O2 species before the introduction of H−.

Highlights

We utilized nanoporous mayenite (12CaO·7Al2O3), a cost-effective material, in the hydride state (H−) to explore the possibility of its use for hydrogen storage and transportation
We propose the use of the nanocage structure of mayenite in the hydride state (H−) for the storage and safe transportation of hydrogen
The X-ray diffractometer (XRD) profile of the mayenite sample prepared before H2 gas treatment agrees well with that of the Ca6Al7O16 structure (Inorganic Crystal Structure Database (ICSD) No 241241) having a cubic system with I43d space group (No 220)

Summary

Introduction

We utilized nanoporous mayenite (12CaO·7Al2O3), a cost-effective material, in the hydride state (H−) to explore the possibility of its use for hydrogen storage and transportation. The observed temperature versus gas evolution profile of the mayenite sample hydrogen treated at 1250 °C for 2 h shows a strong evolution peak of H 2 centered at approximately 600 °C (from IC m/z = 2 band of MS). We estimated the structural parameters of H atom and H − ion in C a6Al7O16 with and without H2 treatment by the Rietveld analysis using time-of-flight (TOF) neutron diffraction data.

Results

Conclusion