Low‐Temperature Methanol‐Water Reforming Over Alcohol Dehydrogenase and Immobilized Ruthenium Complex

Abstract

Hydrogen is one of the most promising sustainable energy carriers for its high gravimetric energy density and abundance. Nowadays, hydrogen production and storage are the main constraints for its commercialization. As a current research focus, hydrogen production from methanol‐water reforming, especially at low temperature, is particularly important. In this study, a novel reaction path for low‐temperature methanol reforming through synergistic catalysis was developed. Alcohol dehydrogenase (ADH) and coenzyme I (nicotinamide adenine dinucleotide, NAD+) were employed for methanol catalytic dehydrogenation at low temperature, which could generate formaldehyde and reductive coenzyme I (NADH). Covalent triazine framework‐immobilized ruthenium complex (Ru‐CTF) was prepared afterwards. On one hand, the catalyst exhibited high activity for the formaldehyde–water shift reaction to generate hydrogen and carbon dioxide. On the other hand, the NADH dehydrogenation was also catalyzed by the Ru‐CTF, producing NAD+ and hydrogen. Additionally, the catalyst also showed high biocompatibility with ADH. Through the synergistic effect of the above two main processes, methanol could be converted into hydrogen and carbon dioxide stably at low temperature for more than 96 h. The hydrogen production rate was dependent on the pH of the reaction solution as well as the ADH dosage. A hydrogen production rate of 157 mmol h−1 mol−1Ru was achieved at the optimum pH (8.1). Additionally, the hydrogen production rate increased linearly with the ADH dosage, reaching 578 mmol h−1 mol−1Ru when the ADH dosage was 180 U at 35 °C. This research could not only help overcome the difficulties for methanol reforming near room temperature but also give new inspiration for designing new reaction pathways for methanol reforming.

Ruthenium Metal–Organic Frameworks as Stable Nanostructures for Selective Hydrogen Production from Acetaldehyde and Water under Mild Conditions

“…Therefore, inexpensive and safe methods to produce and store hydrogen are desperately in demand and have become an essential research direction now. Because of their high gravimetric hydrogen content, organic liquids have attracted much interest in hydrogen production and storage. − The hydrogen production contents from methanol, formic acid, and formaldehyde in water are 12, 4.4, and 8.3 wt %, respectively, which have made these C 1 organics research hotspots. − Various catalysts have been developed for selective decompositions of these compounds. The C–H and C–O bonds of these C 1 organics can be activated by catalysts during a hydrogen-releasing process, demonstrating some methods for hydrogen production and storage. , Actually, the relevant C 2 organics have higher gravimetric hydrogen content, higher energy density, and lower damage compared to corresponding C 1 organics.…”

Enabling alcohol as a hydrogen carrier using metal–organic framework-stabilized Ir–Sc bifunctional catalytic sites

“…Noble metal-based (Ir-, Ru-and Rh-) complexes can efficiently catalyze both the alcohol dehydrogenation and the aldehyde hydrogenation steps, but thermodynamics of the alcohol dehydrogenation reaction is unfavorable, inhibiting high conversion. [11][12][13] Coupling the alcohol dehydrogenation to acetal formation reaction between the aldehyde and the alcohol can effectively move the thermodynamics of the overall reaction, enabling practical hydrogen releasing from the alcohols. 14 Various Ir-based catalysts are reported to be active for alcohol dehydrogenation.…”