Layer-by-layer assembly of transparent amorphous Co3O 4 nanoparticles/graphene composite electrodes for sustained oxygen evolution reaction

Amorphous Co₃O₄ nanoparticle/graphene composites (Co₃O₄/GR) were fabricated via layer-by-layer (LBL) assembly onto indium tin oxide (ITO) coated conductive glass and applied as a catalyst for efficient oxygen evolution reaction in electrolytic water splitting. A thin uniform graphene layer was deposited onto the ITO surface through electrophoretic deposition (EPD), followed by subsequent deposition of a thin layer of Co₃O₄ nanoparticles onto the graphene surface by chemical bath deposition (CBD) to yield a transparent Co ₃O₄/GR bi-layer. X-ray diffraction spectroscopy (XRD), X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM) were employed to characterise the fabricated composites. The layered Co ₃O₄/GR composite is applied for electrocatalytic oxygen evolution reaction (OER) in 0.1 M KOH and exhibits remarkable catalytic activity with a high Faradaic efficiency (95%) and excellent long-term stability.