Facile synthesis of AgPt nano-pompons for efficient methanol oxidation: Morphology control and DFT study on stability enhancement

Fabrication of Flower-like Rhodium-Doped β-Ni(OH)2 as an Efficient Electrocatalyst for Methanol Oxidation Reaction in Alkaline Media

In this study, β-Ni(OH)₂ with a unique flower-like morphology was synthesized through a hydrothermal method. The doping of Rh in β-Ni(OH)₂ was achieved by a reduction method. The as-synthesized catalysts were characterized by X-ray diffraction, transmission electron microscopy, and X-ray photoelectron spectroscopy for the crystal structure, morphology, composition, and chemical state analysis. The electrochemical tests revealed that the doping of Rh can significantly increase the electrocatalytic performance of β-Ni(OH)₂ in 1.0 M KOH solution. The methanol oxidation peak current density of Rh-doped β-Ni(OH)₂ reached 95 mA cm^-2 with a Tafel slope of 40 mV dec^-1. The reason for these improvements is that Rh can suppress the phase transformation of NiOOH from β to α. Meanwhile, the electronic structure change of nickel in β-Ni(OH)₂ and the defect ratio increase caused by Rh doping are beneficial to methanol oxidation reaction (MOR) catalytic activity. Furthermore, the synergistic effect between Rh and Ni(OH)₂ improved the surface activity of β-NiOOH. The doping of Rh in β-Ni(OH)₂ is initiative in this work, which provides a new strategy to design highly efficient and cost-effective MOR electrocatalysts for alkaline DMFCs.