TY - JOUR
T1 - Pristine versus Pyrolyzed Metal-Organic Framework-based Oxygen Evolution Electrocatalysts
T2 - Evaluation of Intrinsic Activity Using Electrochemical Impedance Spectroscopy
AU - Singh, Chanderpratap
AU - Liberman, Itamar
AU - Shimoni, Ran
AU - Ifraemov, Raya
AU - Hod, Idan
N1 - Publisher Copyright:
© 2019 American Chemical Society.
PY - 2019/7/5
Y1 - 2019/7/5
N2 - Metal-organic frameworks (MOFs) have emerged as outstanding electrocatalysts for water oxidation. Commonly, MOFs are utilized for electrocatalytic water oxidation either in pristine or pyrolyzed form. Yet, despite significant advancements in their catalytic performance, further improvement requires new insights on the parameters influencing MOF-based catalysts activity. Here, we have conducted a detailed comparison between the intrinsic electrocatalytic properties of pristine and pyrolyzed Ni-Fe-based MOFs. Interestingly, although pristine MOF exhibits the maximum overall electrocatalytic performance, apparent turnover frequency (TOF) values (intrinsic activity) of all pyrolyzed MOFs exceeded the one of pristine MOF. Moreover, an upper-limit estimation of TOF was extracted using electrochemical impedance spectroscopy (EIS), by excluding IR-drops linked with the electrochemical cell. By doing so, EIS-extracted TOF values were 10-times higher compared to the apparent TOFs. Accordingly, a great leap in performance should still be expected for these catalysts, by designing conductive MOF-platforms having larger pore-diameters to reduce mass-transport limitations.
AB - Metal-organic frameworks (MOFs) have emerged as outstanding electrocatalysts for water oxidation. Commonly, MOFs are utilized for electrocatalytic water oxidation either in pristine or pyrolyzed form. Yet, despite significant advancements in their catalytic performance, further improvement requires new insights on the parameters influencing MOF-based catalysts activity. Here, we have conducted a detailed comparison between the intrinsic electrocatalytic properties of pristine and pyrolyzed Ni-Fe-based MOFs. Interestingly, although pristine MOF exhibits the maximum overall electrocatalytic performance, apparent turnover frequency (TOF) values (intrinsic activity) of all pyrolyzed MOFs exceeded the one of pristine MOF. Moreover, an upper-limit estimation of TOF was extracted using electrochemical impedance spectroscopy (EIS), by excluding IR-drops linked with the electrochemical cell. By doing so, EIS-extracted TOF values were 10-times higher compared to the apparent TOFs. Accordingly, a great leap in performance should still be expected for these catalysts, by designing conductive MOF-platforms having larger pore-diameters to reduce mass-transport limitations.
UR - http://www.scopus.com/inward/record.url?scp=85068106098&partnerID=8YFLogxK
U2 - 10.1021/acs.jpclett.9b01232
DO - 10.1021/acs.jpclett.9b01232
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C2 - 31194556
AN - SCOPUS:85068106098
SN - 1948-7185
VL - 10
SP - 3630
EP - 3636
JO - Journal of Physical Chemistry Letters
JF - Journal of Physical Chemistry Letters
IS - 13
ER -