Interface-engineered ZnS QDs@HKUST-1 composite for electrochemical overall water splitting.

Area of Science:

• Materials Science
• Electrochemistry
• Sustainable Energy

Background:

• Global demand for sustainable hydrogen production is rising for a carbon-neutral economy.
• Water splitting is a key pathway for green hydrogen, but catalyst efficiency is limited by kinetics and stability.
• Developing catalysts with high activity, stability, and tunability for water splitting remains a challenge.

Purpose of the Study:

• To design and synthesize a high-performance bifunctional electrocatalyst for overall water splitting.
• To investigate the synergistic effects of ZnS quantum dots (QDs) and HKUST-1 metal-organic framework (MOF) in a composite material.
• To establish a general strategy for creating efficient, durable, and cost-effective electrocatalysts for hydrogen production.

Main Methods:

• A 'bottle-around-the-ship' strategy was employed to synthesize the ZnS QDs@HKUST-1 (ZQH-1) composite.
• The catalytic performance of ZQH-1 was evaluated for oxygen evolution reaction (OER) and hydrogen evolution reaction (HER).
• Physicochemical properties, including structure, morphology, composition, and surface area, were systematically characterized.

Main Results:

• The ZQH-1 composite exhibited excellent bifunctional electrocatalytic activity for overall water splitting.
• Low overpotentials were achieved: 106 mV for OER and 140 mV for HER at 10 mA cm⁻².
• The catalyst demonstrated outstanding durability over 36 hours at 10 mA cm⁻², enabling water splitting at 1.78 V.

Conclusions:

• The synergistic integration of ZnS QDs and HKUST-1 MOF enhances conductivity and active site accessibility, boosting catalytic performance.
• The study highlights the importance of interfacial charge dynamics in QDs@MOF composites for catalysis.
• A viable strategy for designing efficient, durable, and low-cost electrocatalysts for sustainable hydrogen production was established.