Nickel nanoparticle-doped and steam-modified multiscale structure of carbon micro-nanofibers for hydrogen storage: Effects of metal, surface texture and operating conditions

Abstract

Nickel (Ni) metal-containing microporous and graphitic carbon nanofiber (CNF)-based adsorbent was prepared for the first time as a hydrogen (H2) storage material. Ni was in situ dispersed in the activated carbon microfiber (ACF) substrate and it served as the chemical vapor deposition catalyst to grow CNFs on the ACF. The prepared ACF/CNF multi-scale web was modified using steam to increase the BET surface area (SBET) and microporosity content of the material. The H2 storage capacity of the materials was determined at different temperatures (77, 273 and 298 K), and under batch (static) and dynamic (flow) conditions. The comparative data revealed that the SBET of the materials controlled the storage capacity at cryogenic temperature. The positive effects of the graphitic CNFs and the inclusion of metal (Ni) in the materials were evident at elevated temperatures (273 and 298 K). The H2 uptakes under dynamic conditions were determined to be approximately the same as under batch conditions, indicating that the prepared materials can be efficiently used as adsorbents for H2 under flow conditions.