Fig. 3

Enhanced electrodeposition on nitrate-inserted graphite. a Cross-section SEM image of the prepared NiCeO _x H _y deposited on graphite after nitrate ion insertion. b Elemental mapping of C, Ce, Ni, and O. c Cross-section SEM image of NiCeO _x H _y directly deposited on graphite without foregoing anion intercalation. Scale bars, 25 μm. d Relationship between the electrodeposition time and the loading mass of NiCeO _x H _y deposited on carbon paper (CP), graphite (G), nickel foam (NF), and glass carbon (GC). The electrodeposition was performed at a current density of −20 mA cm⁻² in electrolyte containing totally 0.1 M Ni and Ce nitrates