Main group catalysis for H<sub>2</sub> purification based on liquid organic hydrogen carriers.

Hashimoto, Taiki; Asada, Takahiro; Ogoshi, Sensuke; Hoshimoto, Yoichi · Sci Adv · 2022

basic_science · Level V

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Abstract

Molecular hydrogen (H<sub>2</sub>) is one of the most important energy carriers. In the midterm future, a huge amount of H<sub>2</sub> will be produced from a variety of hydrocarbon sources through conversion and removal of contaminants such as CO and CO<sub>2</sub>. However, bypassing these purification processes is desirable, given their energy consumption and environmental impact, which ultimately increases the cost of H<sub>2</sub>. Here, we demonstrate a strategy to separate H<sub>2</sub> from a gaseous mixture of H<sub>2</sub>/CO/CO<sub>2</sub>/CH<sub>4</sub> that can include an excess of CO and CO<sub>2</sub> relative to H<sub>2</sub> and simultaneously store it in N-heterocyclic compounds that act as liquid organic hydrogen carriers (LOHCs), which can be applied to produce H<sub>2</sub> by subsequent dehydrogenation. Our results demonstrate that LOHCs can potentially be used for H<sub>2</sub> purification from CO- and CO<sub>2</sub>-rich crude H<sub>2</sub> in addition to their well-established use in H<sub>2</sub> storage.