Coordination Effect-Promoted Durable Ni(OH)₂ for Energy-Saving Hydrogen Evolution from Water/Methanol...

Area of Science:

• Electrochemistry
• Materials Science
• Catalysis

Background:

• Electrocatalytic water splitting for hydrogen generation faces challenges due to slow oxygen evolution reactions (OER).
• Methanol oxidation reactions (MOR) offer a faster alternative to OER, but current nickel-based catalysts lack sufficient activity and stability.
• Developing efficient electrocatalysts is crucial for industrial hydrogen production.

Purpose of the Study:

• To synthesize a novel three-dimensional (3D)-networking Mo-doped Ni(OH)2 electrocatalyst with ultralow Ni-Ni coordination.
• To evaluate the electrocatalyst's performance in methanol oxidation reactions (MOR) and hydrogen evolution with formate co-generation.
• To elucidate the structure-activity relationships governing the enhanced catalytic performance.

Main Methods:

• Synthesis of 3D-networking Mo-doped Ni(OH)2.
• Electrochemical characterization including cyclic voltammetry and chronoamperometry.
• Mechanistic studies using density functional theory (DFT) and X-ray absorption spectroscopy (XAS).

Main Results:

• The Mo-doped Ni(OH)2 catalyst exhibited high MOR activity (100 mA cm⁻² at 1.39 V) with a low Tafel slope (28 mV dec⁻¹).
• Enhanced hydrogen evolution performance with formate co-generation achieved >500 mA cm⁻² at 2.00 V for 50 hours in 6 M KOH.
• Ultralow Ni-Ni coordination, 3D-networking structures, and Mo dopants were identified as key factors for improved activity and stability.

Conclusions:

• The novel 3D-networking Mo-doped Ni(OH)2 catalyst offers superior activity and durability for electrocatalytic hydrogen production.
• The findings highlight the potential of tailoring catalyst structure and composition for efficient energy conversion.
• This work provides a new strategy for designing advanced electrocatalysts for industrial applications.