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2H→1T Phase Engineering of Layered Tantalum Disulfides in Electrocatalysis: Oxygen Reduction Reaction
Author(s) -
Luxa Jan,
Mazánek Vlastimil,
Pumera Martin,
Lazar Petr,
Sedmidubský David,
Callisti Mauro,
Polcar Tomáš,
Sofer Zdeněk
Publication year - 2017
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.201701494
Subject(s) - overpotential , catalysis , electrocatalyst , electrochemistry , materials science , electrochemical energy conversion , transition metal , tantalum , chemistry , chemical engineering , inorganic chemistry , metallurgy , electrode , organic chemistry , engineering
Tremendous attention is currently being paid to renewable sources of energy. Transition‐metal dichalcogenides (TMDs) have been intensively studied for their promising catalytic activities in the hydrogen evolution reaction (HER) and the oxygen reduction reaction (ORR). In this fundamental work, we explored the catalytic properties of TMD family members 2H TaS 2 and 1T TaS 2 . Our findings reveal that both polytypes exhibit poor HER performance, which is even more pronounced after electrochemical reduction/oxidation. Our experimental data show that 1T TaS 2 has a lower overpotential at a current density of −10 mA cm −1 , despite theoretical DFT calculations that indicated that the more favorable free energy of hydrogen adsorption should make “perfect” 2H TaS 2 a better HER catalyst. Thorough characterization showed that the higher conductivity of 1T TaS 2 and a slightly higher surface oxidation of 2H TaS 2 explains this discrepancy. Moreover, changes in the catalytic activity after electrochemical treatment are addressed here. For the ORR in an alkaline environment, the electrochemical treatment led to an improvement in catalytic properties. With onset potentials similar to that of Pt/C catalysts, TaS 2 was found to be an efficient catalyst for the ORR, rather than for proton reduction, in contrast to the behavior of Group 6 layered TMDs.