High-Entropy Spinel Oxides-Decorated MXene Nanoarchitectures for Efficient Methanol Oxidation-Assisted Hydrogen...

Area of Science:

• Electrochemistry
• Materials Science
• Catalysis

Background:

• Conventional water electrolysis for hydrogen production relies on the oxygen evolution reaction (OER), which is energy-intensive.
• Substituting OER with the methanol oxidation reaction (MOR) offers a pathway to enhance hydrogen production efficiency and valorize methanol.

Purpose of the Study:

• To design and synthesize novel high-entropy spinel oxide-decorated Ti3C2Tx MXene (HEO/MX) nanoarchitectures.
• To investigate the bifunctional catalytic activity of HEO/MX for both hydrogen evolution reaction (HER) and selective methanol-to-formate conversion.
• To evaluate the performance of a coupled HER-MOR electrolytic cell using the developed electrocatalyst.

Main Methods:

• Fabrication of HEO/MX hybrid nanoarchitectures.
• Electrochemical characterization including cyclic voltammetry, linear sweep voltammetry, and chronoamperometry.
• Assembly and testing of a HER-MOR electrolytic cell.

Main Results:

• The HEO/MX nanoarchitecture demonstrated efficient bifunctional catalysis for HER and MOR.
• Optimized anodic MOR performance was achieved with an oxidation voltage of 1.53 V vs RHE to reach 100 mA cm⁻².
• The cathodic HER required an overpotential of 140 mV to achieve 10 mA cm⁻² in an alkaline medium.
• A coupled HER-MOR cell using HEO/MX operated at 1.59 V for 10 mA cm⁻², outperforming a commercial Pt/C || RuO2 system (1.68 V).

Conclusions:

• The developed HEO/MX hybrid nanoarchitecture is a promising bifunctional electrocatalyst for efficient hydrogen production via coupled HER-MOR.
• The strategy of substituting OER with MOR in electrolysis systems, enabled by advanced materials like HEO/MX, offers a competitive alternative for sustainable hydrogen generation.