MnMoO₄ nanosheet array: an efficient electrocatalyst for hydrogen evolution reaction with enhanced activity over a...

Area of Science:

• Materials Science
• Electrochemistry
• Catalysis

Background:

• Developing efficient electrocatalysts for the hydrogen evolution reaction (HER) is crucial for sustainable hydrogen production.
• Existing catalysts often face limitations in activity, stability, or applicability across different pH environments.
• Nanostructured materials offer unique advantages due to their high surface area and tunable properties.

Purpose of the Study:

• To synthesize and characterize a manganese molybdenum oxide nanosheet array on nickel foam (MnMoO₄ NSA/NF) as a 3D electrocatalyst.
• To evaluate the electrocatalytic performance of MnMoO₄ NSA/NF for the hydrogen evolution reaction (HER) under acidic, basic, and neutral conditions.
• To investigate the stability and potential mechanisms behind the observed catalytic activity.

Main Methods:

• Preparation of MnMoO₄ nanosheet array on nickel foam (MnMoO₄ NSA/NF) via a facile synthesis method.
• Electrochemical characterization using cyclic voltammetry (CV) and chronoamperometry to assess HER performance.
• Evaluation of catalytic activity by measuring overpotentials required to achieve specific current densities (10 mA cm⁻²).
• Stability testing through continuous CV cycling under diverse pH conditions.

Main Results:

• The MnMoO₄ NSA/NF electrode exhibited efficient HER activity across acidic (0.5 M H₂SO₄), basic (1.0 M KOH), and neutral (1.0 M PBS, pH 7) conditions.
• Required overpotentials were 89 mV (acidic), 105 mV (basic), and 161 mV (neutral) to reach 10 mA cm⁻² current density.
• The catalyst demonstrated excellent long-term stability with negligible activity decrease after 1000 CV cycles in various pH solutions.

Conclusions:

• The MnMoO₄ NSA/NF material is a highly effective and stable 3D electrocatalyst for the hydrogen evolution reaction.
• The synergistic effects between Mn and Mo atoms, abundant active sites, and efficient electron transport contribute to its superior performance.
• This catalyst presents a promising candidate for integration into water splitting devices for industrial hydrogen production.