Gel-Print-Grow: A New Way of 3D Printing Metal-Organic Frameworks

Abstract

3D printing offers an attractive means of forming structured metal-organic frameworks (MOFs), as this technique imparts digital geometric tuning to fit any process column. However, 3D-printed MOF structures are usually formed by suspending presynthesized particles into an ink for further processing. This leads to poor rheological properties as MOFs do not bind with inert binders. Herein, we address this problem by coordinating the MOF secondarily by 3D printing its gelated precursors. Specifically, we produced a printable sol-gel containing ∼70 wt % of HKUST-1 precursors and optimized the in situ growth conditions by varying the desolvation temperature and activation solvent. Analysis of the so-called gel-print-grow monoliths' properties as a function of the coordination variables revealed that desolvating at 120 °C produced fully formed MOF particles with comparable diffractive indices to the parent powder regardless of the activation solvent used. Assessment of the samples' textural properties revealed that washing in acetone or methanol produced the highest surface areas, pore volumes, and CO2 adsorption capacities, however, washing with methanol produced binder swelling and collapse of the printed structure, thereby indicating that washing with acetone was more effective overall. This study represents a promising way of 3D printing MOFs and a breakthrough in additive manufacturing, since the simple, high-throughput, framework detailed herein - whereby the synthesis temperature and washing solvent are varied to optimize MOF coordination - could easily be applied to other crystallites. As such, it is anticipated that this new and exciting method will provide new paths to shape engineer MOFs for applications in energy-intensive fields and beyond.

Department(s)

Chemical and Biochemical Engineering

Comments

The involvement of Shane Lawson in this work was sponsored by the National Science Foundation internship program (NSF INTERN-1802049).

International Standard Serial Number (ISSN)

1944-8244; 1944-8252

Document Type

Article - Journal

Document Version

Citation

File Type

text

Language(s)

English

Rights

© 2020 American Chemical Society (ACS), All rights reserved.

Publication Date

16 Dec 2020

PubMed ID

33274935

Link to Full Text

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