Lignin-based porous carbon for efficient hydrogen storage

Abstract

Abstract The intermittent nature of renewable energy generation and the need for energy storage and transportation systems pose considerable challenges to the widespread adoption of hydrogen-based technologies. Producing good hydrogen adsorbents and the efficient storage and transportation of hydrogen are critical for enabling the widespread adoption and utilization of hydrogen as a clean fuel. This study aims to synthesize renewable carbon materials from lignin waste to adsorb hydrogen gas. To this end, lignin-derived porous carbon materials are chemically activated with chemical activators (KOH, NaOH, and ZnCl2). The specific surface area of the raw lignin increased from 0.9 m2 g–1 to a maximum of 2049 m2 g–1 with a pore volume of 0.95 cm3 g–1. At a KOH/lignin ratio of 3, the proposed material adsorbs hydrogen up to 2.42 wt.% at 1 bar and 77 K because of the highly microporous carbons and the major pore size distribution of ~ 0.6 nm. This is attributed to hydrogen adsorption achieved by enhancing the van der Waals forces between hydrogen molecules and the large surface area of the micropores. Further, this paper discusses factors that affect hydrogen uptake based on the characteristics of the developed materials. These findings indicate that hydrogen adsorbents produced using lignin biomass have the potential to be an effective alternative for hydrogen storage and transportation because they are not only cost-effective and eco-friendly, but also more capable than the existing materials.