Lanthanum-doped α-Ni(OH)2 1D-2D-3D hierarchical nanostructures for robust bifunctional electro-oxidation

The development of advanced electrocatalysts for electro-oxidation reactions has attracted much attention because of the critical role of such electrocatalysts in improving the overall efficiency of coupled hydrogen production. We have developed an efficient lanthanum-doped alpha-Ni(OH)(2) bifunctional catalyst with a 1D-2D-3D hierarchical nanostructure. It shows superior activity and stability in the anodic oxygen evolution reaction (OER) and urea oxidation reaction (UOR). Enrichment of the edge sites and conducting La doping in alpha-Ni(OH)(2) phase enable formation and stabilization of abundant local Ni3+ ions. This guarantees ultralow onset potentials in electro-oxidation reactions. The 1D-2D-3D hierarchical nanostructure significantly boosts the in situ generation of high-valence active species, which results in efficient and stable OER and UOR performances, and the synergistic merit of doping-induced facile reaction kinetics. Because of the structural benefits of a large surface area, charge-transfer promotion, good structural stability, and bifunctionality, a 1% La-doped alpha-Ni(OH)(2) hierarchical nanostructure gives superior OER and UOR performances with low overpotentials, large catalytic current densities, and excellent operational stability. It is therefore a promising catalyst for use in simultaneous alkaline wastewater treatment and hydrogen production. (C) 2021 Chinese Society of Particuology and Institute of Process Engineering, Chinese Academy of Sciences. Published by Elsevier B.V.