Enhanced electrocatalytic activity of graphitic carbon nitride-supported Ni/NiO microflower structures for urea electro-oxidation

BACKGROUNDIn this study, a 3D heterostructure of Ni/NiO microflower-decorated graphitic carbon nitride (g-C3N4) with different ratios was synthesized using the hydrothermal method. The aim was to investigate the electrocatalytic activity of these materials toward urea electrochemical oxidation (UEO) and compare them with various Ni-based catalysts in NaOH solution.RESULTSThe crystal structure and morphology of the synthesized electrocatalysts were characterized using X-ray diffraction, transmission electron microscopy, scanning electron microscopy, and energy-dispersive X-ray spectroscopy. Among the different ratios studied, the Ni/NiO 30%/g-C3N4 nanocomposites exhibited the highest electrocatalytic activity and stability. The anodic current density of Ni/NiO 30%/g-C3N4 was approximately 1.5 times higher than that of NiO microflowers, indicating its superior capability for facilitating the electro-oxidation of urea at its surface. Furthermore, the Ni/NiO 30%/g-C3N4 composition showed a lower Tafel slope, low charge transfer resistance, and higher current density, making it a promising material for urea fuel cells.CONCLUSIONThe results of this study highlight the significance of the Ni/NiO 30%/g-C3N4 composition in achieving efficient electrocatalytic activity for UEO. The 3D heterostructure design, combining the synergistic effects of Ni/NiO and g-C3N4, offers enhanced performance and stability. These findings contribute to the development of advanced electrocatalysts for urea fuel cells, with potential applications in energy conversion systems. Further research should focus on optimizing the composition and exploring the underlying mechanisms to improve the performance of these electrocatalysts for practical applications. (c) 2023 Society of Chemical Industry (SCI).