Selective Hydrogen Evolution Reaction in HMF-Containing Mild-Alkaline Electrolytes on Structurally Engineered...

Area of Science:

• Materials Science
• Electrochemistry
• Renewable Energy

Background:

• Alkaline water electrolysis can be made more energy-efficient by replacing the oxygen evolution reaction (OER) with biomass-derived molecule oxidation.
• A key challenge is finding cathode materials selective for the hydrogen evolution reaction (HER) in the presence of organic substrates.

Purpose of the Study:

• To synthesize and evaluate a novel MoS2 nanosheet@graphene nanoplatelet (MoS2 Nsh@GNP) composite as a cathode material.
• To demonstrate its effectiveness for hydrogen production in mild-alkaline media with hydroxymethylfurfural (HMF).

Main Methods:

• Synthesis of MoS2 Nsh@GNP composite.
• Electrocatalytic performance testing using cyclic voltammetry and chronoamperometry.
• Analysis of HER selectivity and byproduct formation via microgas chromatography and 1H NMR.

Main Results:

• The MoS2 Nsh@GNP composite exhibited excellent charge transport properties.
• Low overpotentials of -0.32 V at 10 mA cm-2 and -0.49 V at 100 mA cm-2 were achieved in 0.1 M NaOH + 1 M Na2SO4 (pH ~13).
• HER selectivity was maintained up to 30 mM HMF, with stable operation at pH 13.

Conclusions:

• The MoS2 Nsh@GNP composite is a promising noble-metal-free cathode material for biomass-assisted alkaline electrolysis.
• Its stability and selectivity make it suitable for membraneless electrolysis systems.
• This approach offers a pathway for simultaneous hydrogen production and value-added chemical generation.