Effects of heat treatment temperature on the morphology, composition, and electrocatalytic properties of electrodeposited nib thin films towards OER
Date
2022-07-25
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Abstract
"In this study, we evaluate the morphology, composition, and electrocatalytic properties of NiB films formed by electrodeposition and thermally treated at 520 and 650 °C. The films were characterized by thermogravimetric analysis, scanning electron microscopy, atomic force microscopy, glow discharge spectroscopy, and X-ray diffraction. The morphology and composition of the films were affected by the thermal treatment, showing an increase and decrease in oxygen and boron concentrations respectively. This behavior is associated with the decomposition of the Ni2B and Ni3B, as well as the formation of NiO with increasing temperature. Linear voltammetry, chronoamperometry, and electrochemical impedance spectroscopy were used to evaluate the electrocatalytic activity of the films towards the oxygen evolution reaction (OER). NiB films without thermal treatment showed the lowest onset potential for the OER (1.47 V vs RHE), overpotential (400 mV), Tafel slope (68 mV dec −1 ), and charge transfer resistance (2.4 Ω). This finding reveals that the NiB electrocatalyst without thermal treatment presents similar or superior performance to other electrocatalysts reported in the literature. While the OER kinetics of the NiB electrocatalyst decreases when it is thermally treated at 520 or 650 °C because of the possible Ni2B and Ni3B decompositions and NiO formation".