Dimethyl Ether as Circular Hydrogen Carrier: Low‐Temperature Steam Reforming Over Copper–Zeolite Bifunctional Catalysts

ABSTRACT In the context of a green H 2 ‐based economy, chemical H 2 carriers are essential for efficient H 2 storage and transportation. Among H 2 carriers, dimethyl ether (DME) is a promising candidate due to its characteristics, such as non‐toxicity, easy transportation, high H 2 storage capacity, and its circular nature by the reusability of CO 2 formed from DME steam reforming (DME SR). H 2 stored in DME can be released via DME SR over a bifunctional catalyst, consisting of a solid acid and a metal‐based catalyst. The reaction conditions, in particular, the reaction temperature, are crucial for an efficient H 2 release and depend on the catalysts employed. This concept paper first highlights DME synthesis by CO 2 hydrogenation and then discusses in detail the advances for DME SR at temperatures below 300°C. The kinetic and thermodynamic limitations for DME SR as well as challenges due to side reactions are presented. Zeolites are discussed as promising candidates for low‐temperature applications for the DME hydrolysis step and current insights into structure–activity relationships are highlighted. Catalyst deactivation due to coking and possible regeneration strategies are presented and last, perspectives for developing optimized catalysts for low‐temperature DME SR are provided.