Title: Probing Activities of Individual Catalytic Nanoflakes by Tunneling Mode of Scanning Electrochemical Microscopy

Abstract

The tunneling mode of scanning electrochemical microscopy (SECM) was developed recently and applied to studies of charge-transfer reactions at single metal nanoparticles (NPs). When an SECM tip is brought within the tunneling distance from a conductive NP, the particle begins to act as a part of the nanoelectrode. Herein, we demonstrate the possibility of using carbon nanoelectrodes with a very thin insulating sheath for electrochemical tunneling experiments at flat samples. In this way, electrocatalytic activity, conductivity, and charging properties of and faradaic processes in layered nanomaterials can be characterized by single-nanoflake voltammetry without making direct ohmic contact with them. A broad applicability of tunneling SECM experiments is demonstrated by probing nanomaterials with different size, geometry, and electrocatalytic properties, including metallic/pseudo-metallic (1T/1T') and semiconducting (2H) MoS₂ nanoflakes, N-doped porous carbon catalyst, and MXene nanosheets. Further, the Tafel plots for the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) at individual nanoflakes are compared to analogous measurements for an ensemble of flakes attached to the surface of a macroscopic electrode. Moreover, we observed variations in catalytic activities of individual MXene flakes toward HER and OER caused by non-uniform doping.

Authors:

Bo, Tianyu ^[1]; Wang, Xiang  ^[1];

• Search DOE PAGES for author "Wang, Xiang"
• Search DOE PAGES for ORCID "0000-0002-9558-7849"

Jia, Rui  ^[1];

• Search DOE PAGES for author "Jia, Rui"
• Search DOE PAGES for ORCID "0000-0002-6094-982X"

Han, Lili ^[2]; Xin, Huolin L.  ^[2];

• Search DOE PAGES for author "Xin, Huolin L."
• Search DOE PAGES for ORCID "0000-0002-6521-868X"

Zhang, Hanyu ^[3]; Miller, Elisa M.  ^[3];

• Search DOE PAGES for author "Miller, Elisa M."
• Search DOE PAGES for ORCID "0000-0002-7648-5433"

Mirkin, Michael V.  ^[1]

• Search DOE PAGES for author "Mirkin, Michael V."
• Search DOE PAGES for ORCID "0000-0002-3424-5810"

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+ Show Author Affiliations

1. Queens College, Flushing, NY (United States); City Univ. of New York (CUNY), NY (United States)
2. Univ. of California, Irvine, CA (United States)
3. National Renewable Energy Lab. (NREL), Golden, CO (United States)

Publication Date:

Fri Nov 12 00:00:00 EST 2021

Research Org.:

National Renewable Energy Lab. (NREL), Golden, CO (United States)

Sponsoring Org.:

USDOE Office of Science (SC), Basic Energy Sciences (BES); National Science Foundation (NSF)

OSTI Identifier:

1837996

Report Number(s):

NREL/JA-5900-80762
Journal ID: ISSN 1932-7447; MainId:77546;UUID:b2338d1f-57ab-4852-9f28-faeb366bab20;MainAdminID:63524

Grant/Contract Number:  

AC36-08GO28308; CHE-2102298; CHE-1900401

Resource Type:

Accepted Manuscript

Journal Name:

Journal of Physical Chemistry. C

Additional Journal Information:

Journal Volume: 125; Journal Issue: 46; Journal ID: ISSN 1932-7447

Publisher:

American Chemical Society

Country of Publication:

United States

Language:

English

Subject:

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY; carbon; catalyst activity; charge transfer; layered semiconductors; metal nanoparticles; nanostructured materials; ohmic contacts; porous materials; scanning electron microscopy; scanning probe microscopy; solar-photochemistry