Mott-Schottky Heterojunction on Self-Supporting TiO₂ Nanotubes Enables Efficient and Stable Chlorine Evolution...

Area of Science:

• Electrochemistry
• Materials Science
• Catalysis

Background:

• The chlorine evolution reaction (CER) is crucial for chemical manufacturing but faces challenges like catalyst deactivation and oxygen evolution.
• Existing catalysts, such as Ru-RuO2/Ti plates and dimensionally stable anodes, exhibit limitations in selectivity and operational stability.

Purpose of the Study:

• To design and demonstrate a novel Mott-Schottky heterojunction electrocatalyst for efficient and stable CER.
• To overcome catalyst deactivation and oxygen evolution competition in CER.

Main Methods:

• In situ growth of Ruthenium-Ruthenium dioxide (Ru-RuO2) nanoparticles on Titanium dioxide (TiO2) nanotubes (NTs) to form a heterojunction.
• Characterization of the catalyst's electronic properties, including work function differences and built-in electric fields.
• Electrochemical testing to evaluate CER performance, selectivity, and long-term stability.

Main Results:

• The Ru-RuO2/TiO2 NTs electrode exhibited a low overpotential of 43 mV at 50 mA cm-2 for CER.
• Achieved high Cl2 selectivity of 95.8% and remarkable stability over 600 hours at 100 mA cm-2.
• Outperformed traditional Ru-RuO2/Ti plate (87.7% selectivity, ~70 h stability) and dimensionally stable anodes (84.8% selectivity, ~100 h stability).

Conclusions:

• The Mott-Schottky heterojunction strategy effectively enhances catalyst performance and stability for CER.
• The self-supporting Ru-RuO2/TiO2 NTs catalyst presents a viable pathway for advancing the chlor-alkali industry and environmental protection.
• Optimized intermediate adsorption and catalyst-support interaction contribute to the superior performance.