Molecular Solar Thermal Batteries through Combination of Magnetic Nanoparticle Catalysts and Tailored Norbornadiene Photoswitches. Issue 15 (22nd February 2021)

• Record Type: Journal Article
• Authors: Lorenz, Patrick; Luchs, Tobias; Hirsch, Andreas
• Is Part Of: Chemistry. Volume 27:Issue 15(2021)
• Page Start: 4993
• Page End: 5002
• Publication Date: 2021-02-22
• Subjects: magnetic catalysts -- nanoparticles -- norbornadiene -- process heat -- solar energy storage; Chemistry -- Periodicals; 540
• DOI: 10.1002/chem.202005427
• Languages: English
• ISSNs: 0947-6539

Abstract

Abstract: Cobalt catalysts are immobilized on the surface of iron oxide nanoparticles for the preparation of highly active quasi‐homogeneous catalysts toward an efficient release of photochemically stored energy in norbornadiene‐based photoswitches. The facile separation of the iron oxide nanoparticles through exploitation of the intrinsic magnetic properties of this material enables efficient cyclization of energy storage and release. Through the transition from cobalt (II) salphen to cobalt porphyrins, a 22.6‐fold increase in the catalytic efficiency of the QC‐NBD back‐conversion is achieved, with an initial TOF of up to 3.64 s −1 and excellent TON of over 3305. In addition, a series of novel "push–pull" functionalized norbornadiene derivatives is prepared, featuring excellent absorption properties with maxima up to 366 nm, quantum yields around 70 %, high energy storage capacities of up to 98.0 kJ mol −1, and outstanding thermal stability with t 1/2 (25 °C) over 100 days. Finally, the energy storage potential of these molecular solar thermal (MOST) systems is harnessed in a heat release experiment. This demonstrates the potential of norbornadiene‐based photoswitches in combination with efficient magnetic catalysts for the generation of environmentally benign process heat. Abstract : Energy storage : A molecular solar thermal battery is presented, which is based on modified norbornadiene (NBD)/quadricyclane (QC) photoswitches and magnetic nanoparticle catalysts. A library of NBD/QC derivatives is prepared with absorption onsets of up to 450 nm, high energy storage capacities of up to 98.0 kJ mol −1, and long storage potentials ( t 1/2 up to 611 days). Detailed performance analysis of the novel magnetic NP catalysts is conducted, revealing stability against desorption and high activity with initial TOFs of 3.64 s −1 and TON of more than 3305.