Achieving solid-state room temperature dehydrogenation from sodium borohydride composited with glycolic acid

Abstract

Sodium borohydride (NaBH₄) has long been regarded as a cost-effective hydrogen storage material with a theoretical hydrogen storage capacity of 10.6 wt%. However, its practical application is hindered by thermodynamic stability, and traditional hydrogen production from NaBH₄ required excess water, which lowered its volumetric and gravimetric capacities. In this study, for the first time, solid-state glycolic acid (GA) was used to destabilize NaBH₄ for producing hydrogen. According to the results, NaBH₄-GA started releasing hydrogen rapidly from room temperature and more than 3.6 wt% hydrogen was produced below 100 ℃ with efficient hydrogen utilization rate of 95%. Moreover, NaBH₄-GA composites maintained solid-state through the entire dehydrogenation process with high volumetric capacity above 39 g H₂ L^-1. Through the evolution of bonding structures and composition in NaBH₄-GA composites, the dehydrogenation process was further confirmed as similar to the hydrolysis process of NaBH₄, but with no liquid appearing. This chemical process “solid-state hydrolysis” may offer potential application and novel insights in low-temperature solid-state hydrogen storage using NaBH₄.