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2. Local Electric Field Effects on Water Dissociation in Bipolar Membranes Studied Using Core–Shell Catalysts

Author

Sarma, Prasad V., Kramar, Boris V., Chen, Lihaokun, Sasmal, Sayantan, Weingartz, Nicholas P., Huang, Jiawei, Mitchell, James B., Kwak, Minkyoung, Chen, Lin X., and Boettcher, Shannon W.

Abstract

The local electric field strength is thought to affect the rate of water dissociation (WD) in bipolar membranes (BPMs) at the catalyst–nanoparticle surfaces. Here, we study core–shell nanoparticles, where the core is metallic, semiconducting, or insulating, to understand this effect. The nanoparticle cores were coated with a WD catalyst layer (TiO2or HfO2) via atomic layer deposition (ALD), and the morphology was imaged with transmission electron microscopy. Irrespective of the core material, these core–shell catalysts displayed comparable WD overpotentials at optimal mass loading, despite the hypothesized differences in the electric field strength across the catalyst particle suggested by continuum electrostatic simulations. Substantial atomic interdiffusion between the core and shell was ruled out by X-ray absorption spectroscopy, X-ray photoelectron spectroscopy, and diffuse reflectance optical measurements. However, the optimal mass loading of catalyst was roughly 1 order of magnitude higher for the conductive and high dielectric core materials than for the low dielectric insulating cores. These findings are consistent with the hypothesis that electric field screening within the core material focuses the electric field drop between particles such that larger film thicknesses can be tolerated. Collectively, these data support the idea that it is the local electric field at the molecular level that controls proton-transfer rates and that the metal core/dielectric-shell constructs introduced here modulate that field. Further materials and synthetic design may enable optimization of the electric field strength across the proton-transfer trajectory at the material surface.

Published
2024
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3. Versatile sulfidation of a metal-organic framework via heterolytic splitting of organo sulfides at distorted Zr-nodes

Author

Wang, Qining, primary, Vornholt, Simon M., additional, Melix, Patrick, additional, Formalik, Filip, additional, Chen, Zhihengyu, additional, Tufaro, Luke M., additional, Liu, Jian, additional, Kramar, Boris V., additional, Wang, Zhiwei, additional, Chen, Lin X., additional, Snurr, Randall Q., additional, Chapman, Karena W., additional, Notestein, Justin M., additional, and Hupp, Joseph T., additional

Published
2023
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6. Photoreactive Carbon Dioxide Capture by a Zirconium–Nanographene Metal–Organic Framework

Author

Zheng, Xin, primary, Drummer, Matthew C., additional, He, Haiying, additional, Rayder, Thomas M., additional, Niklas, Jens, additional, Weingartz, Nicholas P., additional, Bolotin, Igor L., additional, Singh, Varun, additional, Kramar, Boris V., additional, Chen, Lin X., additional, Hupp, Joseph T., additional, Poluektov, Oleg G., additional, Farha, Omar K., additional, Zapol, Peter, additional, and Glusac, Ksenija D., additional

Published
2023
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7. Photoreactive CO2 Capture by a Zr-Nanographene MOF

Author

Zheng, Xin, primary, Drummer, Matthew C., additional, He, Haiying, additional, Saffar Avval, Shirin, additional, Rayder, Thomas M., additional, Niklas, Jens, additional, Weingartz, Nicholas P., additional, Singh, Varun, additional, Kramar, Boris V., additional, Chen, Lin X., additional, Hupp, Joseph T., additional, Poluektov, Oleg G., additional, Farha, Omar K., additional, Chaplin, Brian P., additional, Zapol, Peter, additional, and Glusac, Ksenija D., additional

Published
2022
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10. Single-Atom Metal Oxide Sites as Traps for Charge Separation in the Zirconium-Based Metal–Organic Framework NDC–NU-1000

Author

Kramar, Boris V., primary, Phelan, Brian T., additional, Sprague-Klein, Emily A., additional, Diroll, Benjamin T., additional, Lee, Sungsik, additional, Otake, Ken-ichi, additional, Palmer, Rebecca, additional, Mara, Michael W., additional, Farha, Omar K., additional, Hupp, Joseph T., additional, and Chen, Lin X., additional

Published
2021
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