Catalytic Activity of Defect-Engineered Transition Me tal Dichalcogenides Mapped with Atomic-Scale Precision by Electrochemical Scanning Tunneling Microscopy

Marco Lunardon, Tomasz Kosmala*, Mahdi Ghorbani-Asl, Arkady V. Krasheninnikov, Sadhu Kolekar, Christian Durante, Matthias Batzill, Stefano Agnoli, Gaetano Granozzi

*Corresponding author for this work

Research output: Contribution to journalArticleScientificpeer-review

13 Citations (Scopus)
42 Downloads (Pure)

Abstract

Unraveling structure-activity relationships is a key objective of catalysis. Unfortunately, the intrinsic complexity and structural heterogeneity of materials stand in the way of this goal, mainly because the activity measurements are area-averaged and therefore contain information coming from different surface sites. This limitation can be surpassed by the analysis of the noise in the current of electrochemical scanning tunneling microscopy (EC-STM). Herein, we apply this strategy to investigate the catalytic activity toward the hydrogen evolution reaction of monolayer films of MoSe2. Thanks to atomically resolved potentiodynamic experiments, we can evaluate individually the catalytic activity of the MoSe2 basal plane, selenium vacancies, and different point defects produced by the intersections of metallic twin boundaries. The activity trend deduced by EC-STM is independently confirmed by density functional theory calculations, which also indicate that, on the metallic twin boundary crossings, the hydrogen adsorption energy is almost thermoneutral. The micro- and macroscopic measurements are combined to extract the turnover frequency of different sites, obtaining for the most active ones a value of 30 s-1 at −136 mV vs RHE.

Original languageEnglish
Pages (from-to)972-980
Number of pages9
JournalACS Energy Letters
Volume8
Issue number2
DOIs
Publication statusPublished - 16 Jan 2023
MoE publication typeA1 Journal article-refereed

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