Title: Reversible Hydrogen Uptake/Release over a Sodium Phenoxide-Cyclohexanolate Pair

Abstract

Hydrogen uptake and release in arene–cycloalkane pairs provide an attractive opportunity for on-board and off-board hydrogen storage. However, the efficiency of arene–cycloalkane pairs currently is limited by unfavorable thermodynamics for hydrogen release. It is shown here that the thermodynamics can be optimized by replacement of H in the -OH group of cyclohexanol and phenol with alkali or alkaline earth metals. The enthalpy change upon dehydrogenation decreases substantially, which correlates with the delocalization of the oxygen electron to the benzene ring in phenoxides. Theoretical calculations reveal that replacement of H with a metal leads to a reduction of the HOMO–LUMO energy gap and elongation of the C-H bond in the α site in cyclohexanolate, which indicates that the cyclohexanol is activated upon metal substitution. The experimental results demonstrate that sodium phenoxide–cyclohexanolate, an air- and water-stable pair, can desorb hydrogen at ca. 413 K and 373 K in the solid form and in an aqueous solution, respectively. Hydrogenation, on the other hand, is accomplished at temperatures as low as 303 K.

Authors:

Yu, Yang ^[1]; He, Teng ^[1]; Wu, Anan ^[2]; Pei, Qijun ^[1]; Karkamkar, Abhijeet ^[3]; Autrey, Tom ^[3]; Chen, Ping  ^[4]

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• Search orcid.org for ORCID "0000-0002-0625-0639"

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+ Show Author Affiliations

1. Chinese Academy of Sciences (CAS), Dalian (China). Dalian Inst. of Chemical Physics
2. Xiamen Univ., Xiamen (China). Fujian Provincial Key Lab. of Theoretical and Computational Chemistry, College of Chemistry and Chemical Engineering
3. Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
4. Chinese Academy of Sciences (CAS), Dalian (China). Dalian Inst. of Chemical Physics, State Key Lab.of Catalysis; Xiamen Univ., Fujian (China). Collaborative Innovation Centre of Chemistry for Energy Materials

Publication Date:

2018-11-25

Research Org.:

Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

Sponsoring Org.:

USDOE Office of Energy Efficiency and Renewable Energy (EERE), Fuel Cell Technologies Office (EE-3F); National Natural Science Foundation of China (NNSFC)

OSTI Identifier:

1490385

Report Number(s):

PNNL-SA-132154
Journal ID: ISSN 1433-7851

Grant/Contract Number:  

AC0576RL01830; 21875246, 51671178, 51472237; 21773193; 2016YFE0118300; 20720160031

Resource Type:

Accepted Manuscript

Journal Name:

Angewandte Chemie (International Edition)

Additional Journal Information:

Journal Name: Angewandte Chemie (International Edition); Journal Volume: 58; Journal Issue: 10; Journal ID: ISSN 1433-7851

Publisher:

Wiley

Country of Publication:

United States

Language:

English

Subject:

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY; hydrogen storage materials; metalation; organic hydrides; thermodynamic modification