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Photocatalytic Hedgehog Particles for High Ionic Strength Environments

Montjoy, Douglas G. and Hou, Harrison and Bahng, Joong Hwan and Eskafi, Aydin and Jiang, Ruiyu and Kotov, Nicholas A. (2021) Photocatalytic Hedgehog Particles for High Ionic Strength Environments. ACS Nano, 15 (3). pp. 4226-4234. ISSN 1936-0851. https://resolver.caltech.edu/CaltechAUTHORS:20210222-100904059

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Abstract

High ionic strength environments can profoundly influence catalytic reactions involving charged species. However, control of selectivity and yield of heterogeneous catalytic reactions involving nano- and microscale colloids remains hypothetical because high ionic strength leads to aggregation of particle dispersions. Here we show that microscale hedgehog particles (HPs) with semiconductor nanoscale spikes display enhanced stability in solutions of monovalent/divalent salts in both aqueous and hydrophobic media. HPs enable tuning of photocatalytic reactions toward high-value products by adding concentrated inert salts to amplify local electrical fields in agreement with Derjaguin, Landau, Verwey, and Overbeek theory. After optimization of HP geometry for a model photocatalytic reaction, we show that high salt conditions increase the yield of HP-facilitated photooxidation of 2-phenoxy-1-phenylethanol to benzaldehyde and 2-phenoxyacetophenone by 6 and 35 times, respectively. Depending on salinity, electrical fields at the HP–media interface increase from 1.7 × 10⁴ V/m to 8.5 × 10⁷ V/m, with high fields favoring products generated via intermediate cation radicals rather than neutral species. Electron transfer rates were modulated by varying the ionic strength, which affords a convenient and hardly used reaction pathway for engineering a multitude of redox reactions including those involved in the environmental remediation of briny and salty water.


Item Type:Article
Related URLs:
URLURL TypeDescription
https://doi.org/10.1021/acsnano.0c05992DOIArticle
ORCID:
AuthorORCID
Montjoy, Douglas G.0000-0003-3675-8596
Bahng, Joong Hwan0000-0003-0997-9625
Kotov, Nicholas A.0000-0002-6864-5804
Additional Information:© 2021 American Chemical Society. Received 18 July 2020; Accepted 8 February 2021; Published online 19 February 2021. The central part of this work was supported by the NSF project 1566460 “Nanospiked Particles for Photocatalysis”. Additional support was provided by NSF 1463474 “Energy- and Cost-Efficient Manufacturing Employing Nanoparticles”, ONR N000141812876, and the Vannewar Bush DoD Fellowship to N.A.K. titled “Engineered Chiral Ceramics”. The work was also supported by ONR Multidisciplinary University Research Initiative Award N00014-18-1-2497. The authors would like to acknowledge the Michigan Center for Materials Characterization (MC2) and NSF grants DMR-0315633 and DMR-0320740 for the use of microscopes in this work. Author Contributions. The manuscript was written through contributions of all authors. All authors have given approval to the final version of the manuscript. The authors declare no competing financial interest.
Funders:
Funding AgencyGrant Number
NSFCHE-1566460
NSFCMMI-1463474
Office of Naval Research (ONR)N00014-18-12876
Vannever Bush Faculty FellowshipUNSPECIFIED
Office of Naval Research (ONR)N00014-18-1-2497
Michigan Center for Materials CharacterizationUNSPECIFIED
NSFDMR-0315633
NSFDMR-0320740
Subject Keywords:spiky particles; electrocatalysis; colloids; noble-metal free; photooxidation; lignin
Issue or Number:3
Record Number:CaltechAUTHORS:20210222-100904059
Persistent URL:https://resolver.caltech.edu/CaltechAUTHORS:20210222-100904059
Official Citation:Photocatalytic Hedgehog Particles for High Ionic Strength Environments. Douglas G. Montjoy, Harrison Hou, Joong Hwan Bahng, Aydin Eskafi, Ruiyu Jiang, and Nicholas A. Kotov. ACS Nano 2021 15 (3), 4226-4234; DOI: 10.1021/acsnano.0c05992
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:108142
Collection:CaltechAUTHORS
Deposited By: George Porter
Deposited On:22 Feb 2021 20:12
Last Modified:25 Mar 2021 16:03

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