Sprouts-like Fe(OH)2 hetero-nanostructures assembly on selenium layered nickel foam (NiF–Se) as an efficient and durable catalyst for electro-oxidation of urea

In this study, we develop selenium (Se)-iron hydroxide (NiF–Se@Fe(OH) 2 ) hetero-nanostructured catalyst system for fuel cell, and environmental-relevant urea-electro-oxidation reaction. For the rational engineering, the Se layers are initially deposited on the Ni foam substrate; then we grow Fe(OH) 2 hetero-nanostructures with various morphologies by introducing different ratios of Fe precursor sample. The Fe(OH) 2 ball-like nanorods to rock-like nanosheets are synthesized on the Se layered Ni foam surface by a simple hydrothermal process. The microscopic characterizations, and spectral analysis reveal the formation of Se integrated Fe(OH) 2 hetero-nanostructures such as ball-like nanorods, sprouts-like nanowire network, nanoflowers and rock-like nanosheets through effective Ni–O bond and Fe–Se bond for its typical synergism. The Se induces an interesting morphology transformation from crystalline nanorods to rock-like nanosheets structures that lead to the potential constituents for catalyst electrode that effectively merge the qualities such as high conductivity, large specific surface area, and larger catalytic active sites for electro-oxidation reaction of urea. Among them, NiF–Se@Fe(OH) 2 (8 mmol Fe(NO 3 ) 2 ) sprouts-like hetero-nanostructured network displays higher catalytic activity toward oxidation of urea (146.7 mA) with onset potential of 0.11 V vs. Ag/AgCl in 1 M NaOH + 0.1 M urea. Furthermore, the sprouts-like NiF–Se@Fe(OH) 2 nanowired network shows superior activity than the other aspect ratio's, excellent long-term stability, and reproducibility.