TY - JOUR

T1 - Origin of Electrocatalytic Activity in Amorphous Nickel-Metalloid Electrodeposits

AU - Sarac, Baran

AU - Karazehir, Tolga

AU - Micusik, Matej

AU - Halkali, Celine

AU - Gutnik, Dominik

AU - Omastova, Maria

AU - Sarac, A. Sezai

AU - Eckert, Jürgen

N1 - Publisher Copyright: © 2021 American Chemical Society.

PY - 2021/5/26

Y1 - 2021/5/26

N2 - In transition metal-based alloys, the nonlinearity of the current at large cathodic potentials reduces the credibility of the linear Tafel slopes for the evaluation of electrocatalytic hydrogen activity. High-precision nonlinear fitting at low current densities describing the kinetics of electrochemical reactions due to charge transfer can overcome this challenge. To show its effectiveness, we introduce a glassy alloy with a highly asymmetric energy barrier: amorphous NiP electrocoatings (with different C and O inclusions) via changing the applied DC and pulsed current and NaH2PO2 content. The highest hydrogen evolution reaction (HER) activity with the lowest cathodic transfer coefficient α = 0.130 with high J0 = −1.07 mA cm–2 and the largest surface areas without any porosity are observed for the pulsed current deposition. The calculated α has a direct relation with morphology, composition, chemical state and coating thickness defined by the electrodeposition conditions. Here, a general evaluation criterion with practicality in assessment and high accuracy for electrocatalytic reactions applicable to different metallic alloy systems is presented.

AB - In transition metal-based alloys, the nonlinearity of the current at large cathodic potentials reduces the credibility of the linear Tafel slopes for the evaluation of electrocatalytic hydrogen activity. High-precision nonlinear fitting at low current densities describing the kinetics of electrochemical reactions due to charge transfer can overcome this challenge. To show its effectiveness, we introduce a glassy alloy with a highly asymmetric energy barrier: amorphous NiP electrocoatings (with different C and O inclusions) via changing the applied DC and pulsed current and NaH2PO2 content. The highest hydrogen evolution reaction (HER) activity with the lowest cathodic transfer coefficient α = 0.130 with high J0 = −1.07 mA cm–2 and the largest surface areas without any porosity are observed for the pulsed current deposition. The calculated α has a direct relation with morphology, composition, chemical state and coating thickness defined by the electrodeposition conditions. Here, a general evaluation criterion with practicality in assessment and high accuracy for electrocatalytic reactions applicable to different metallic alloy systems is presented.

KW - amorphous alloys

KW - Butler-Volmer equation

KW - electrodeposition

KW - energy-dispersive X-ray analysis

KW - linear sweep voltammetry

KW - morphology

KW - nickel phosphide

KW - Raman spectroscopy

UR - http://www.scopus.com/inward/record.url?scp=85106365122&partnerID=8YFLogxK

U2 - 10.1021/acsami.1c03007

DO - 10.1021/acsami.1c03007

M3 - Article

C2 - 33982559

AN - SCOPUS:85106365122

VL - 13.2021

SP - 23689

EP - 23701

JO - ACS Applied Materials and Interfaces

JF - ACS Applied Materials and Interfaces

SN - 1944-8244

IS - 20

ER -