Abstract

Two materials currently of interest for onboard lightweight hydrogen storage applications are sodium aluminum hydride (NaAlH4), a complex metal hydride, and carbon aerogels (CAs), a light porous material connected by several spherical nanoparticles. The objectives of the present work have been to investigate the synthesis, characterization, and hydrogenation behavior of Pd‐, Ti‐ or Fe‐doped CAs, NaAlH4, and MgH2 nanocomposites. The diameters of Pd nanoparticles onto CA’s surface and BET surface area of CAs were 3–10 nm and 700–900 m2g−1, respectively. The H2 storage capacity of metal hydrides has been studied using high‐pressure TGA microbalance and they were 4.0, 2.7, 2.1, and 1.2 wt% for MgH2‐FeTi‐CAs, MgH2‐FeTi, CAs‐Pd, and 8 mol% Ti‐doped NaAlH4, respectively, at room temperature. Carbon aerogels with higher surface area and mesoporous structures facilitated hydrogen diffusion and adsorption, which accounted for its extraordinary hydrogen storage phenomenon. The hydrogen adsorption abilities of CAs notably increased after inclusion of metal hydrides by the “hydrogen spillover” mechanisms.

Highlights

  • Hydrogen is recognized as a clean fuel because of its almost complete combustion in air with notably high energy delivery ability

  • NaAlH4 is different from any other metal hydrides and borohydrides with similar structures since it is capable to reversibly store H2 after doping with transition metals (e.g., Ti, Fe, or Zr) [8,9,10]

  • The synthesis, characterization, and H2 adsorption capacity of carbon aerogels (CAs)/metallic hydride nanocomposites as a catalyst were investigated in the present work

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Summary

Introduction

Hydrogen is recognized as a clean fuel because of its almost complete combustion in air with notably high energy delivery ability. Addition of 1 wt% Pd can be effective for the hydrogen adsorption capacity of FeTi to achieve its theoretical hydrogen storage capacity of 1.9 wt% [31,32,33] As carbon materials such as graphite or CAs have been shown to reduce the hydrogen adsorption and desorption. XANES/EXAFS spectroscopy is an excellent technique for characterizing the valency and local structure of Ti species in a complex Timetal hydride with short-range orders [37,38,39,40,41] These studies are conducted to identify the optimum hydrogen storage capacity for hydrogen storage system. The adsorptive H2 storage capacity was studied using a high-pressure thermogravimetric analyzer

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