• Zabielaite, Ausrine
• Balciunaite, Aldona
• Upskuviene, Daina
• Simkunaite, Dijana
• Niaura, Gediminas
• Norkus, Eugenijus
• Levinas, Ramunas
• Tamašauskaitė-Tamašiūnaitė, Loreta
• Jasulaitiene, Vitalija
• Vaiciuniene, Jurate

Abstract

<jats:p>This study focuses on fabricating cobalt particles deposited on graphitic carbon nitride (Co/gCN) using annealing, microwave-assisted and hydrothermal syntheses, and their employment in hydrogen and oxygen evolution (HER and OER) reactions. Composition, surface morphology, and structure were examined using inductively coupled plasma optical emission spectroscopy, X-ray photoelectron spectroscopy, and X-ray diffraction. The performance of Co-modified gCN composites for the HER and OER were investigated in an alkaline media (1 M KOH). Compared to the metal-free gCN, the modification of gCN with Co enhances the electrocatalytic activity towards the HER and OER. Additionally, thermal annealing of both Co(NO3)2 and melamine at 520 °C for 4 h results in the preparation of an effective bifunctional Co3O4/gCN catalyst for the HER with the lower Eonset of −0.24 V, a small overpotential of −294.1 mV at 10 mA cm−2, and a low Tafel slope of −29.6 mV dec−1 in a 1.0 M KOH solution and for the OER with the onset overpotential of 286.2 mV and overpotential of 422.3 mV to achieve a current density of 10 mA cm−2 with the Tafel slope of 72.8 mV dec−1.</jats:p>

Topics

• nanoparticle
• density
• surface
• Carbon
• x-ray diffraction
• x-ray photoelectron spectroscopy
• Oxygen
• nitride
• composite
• Hydrogen
• cobalt
• annealing
• current density