High-Entropy Metal Interstitials Activate TiO₂ for Robust Catalytic Oxidation

Area of Science:

• Materials Science
• Catalysis
• Electrochemistry

Background:

• Metal doping is key for oxygen activation catalysts, but dopant leaching limits their application in oxidation reactions.
• Developing stable and efficient catalysts for oxygen activation under mild conditions remains a significant challenge.

Purpose of the Study:

• To develop a novel entropy-increase strategy for synthesizing high-entropy metal interstitial functionalized anatase titanium dioxide (HE-TiO2) nanosheets.
• To investigate the structural, electronic, and catalytic properties of the synthesized HE-TiO2 for oxygen activation.
• To demonstrate the potential of this strategy for creating stable and efficient oxygen activation catalysts.

Main Methods:

• Synthesis of high-entropy metal (Mg, Ca, Mn, Fe, Co) interstitial functionalized anatase TiO2 (HE-TiO2) nanosheets using an entropy-increase strategy.
• Characterization using X-ray absorption spectra to confirm metal interstitial formation and lattice distortion.
• Theoretical analysis and in situ synchrotron radiation Fourier transform infrared spectroscopy to understand electronic structure and oxygen adsorption.

Main Results:

• The synthesized HE-TiO2 exhibited intense lattice distortion and lattice expansion, confirming the formation of metal interstitials.
• Metal interstitials were found to populate subgap states in TiO2, facilitating moderate adsorption for efficient oxygen activation.
• The HE-TiO2 demonstrated remarkable degradation efficiency across a wide pH range and exceptional stability in a flow-by electro-catalytic reactor.

Conclusions:

• The entropy-increase strategy provides a universal method for synthesizing high-entropy materials with integrated metal interstitials in metal oxides.
• HE-TiO2 offers enhanced stability and efficiency for oxygen activation, overcoming the limitations of traditional metal doping.
• This work broadens the potential applications of high-entropy materials in catalysis and electrochemistry.