Phase Engineering of Pd-Te Hexagonal Nanoplates for Enhancing Nitrogen Oxidation

Area of Science:

• Materials Science
• Catalysis
• Green Chemistry

Background:

• Photocatalytic conversion of nitrogen (N₂) to valuable nitrate (NO₃⁻) offers an energy-efficient alternative to traditional industrial processes.
• The influence of crystal phase on N₂ oxidation efficiency remains largely unexplored.
• Developing efficient catalysts for N₂ fixation under ambient conditions is crucial for sustainable chemical production.

Purpose of the Study:

• To investigate the crystal phase dependence of Palladium-Tellurium (Pd-Te) hexagonal nanoplates for solar-driven N₂ oxidation to NO₃⁻.
• To identify the optimal Pd-Te phase for maximizing nitrate production efficiency.
• To elucidate the reaction mechanism underlying the phase-dependent photocatalytic activity.

Main Methods:

• Synthesis of Pd-Te hexagonal nanoplates with distinct crystalline phases (Pd₂.₅Te, Pd₂₀Te₇, PdTe).
• Photocatalytic evaluation under full-spectrum irradiation for N₂ to NO₃⁻ conversion.
• In situ characterization using X-ray photoelectron spectroscopy (XPS), electron paramagnetic resonance (EPR), and attenuated total reflection Fourier transform infrared (ATR-FTIR) spectroscopy.

Main Results:

• The Pd₂.₅Te phase exhibited superior photocatalytic performance, achieving a nitrate production rate of 372.2 μmol g⁻¹ h⁻¹.
• This rate was significantly higher (4.4–6.2 times) than that of Pd₂₀Te₇ and PdTe phases.
• In situ studies revealed that photoexcited holes and electrons react with O₂ to form reactive oxygen species (·OH, ·O₂⁻), which activate and oxidize N₂.

Conclusions:

• Crystal phase engineering of Pd-Te nanoplates is a critical factor for enhancing N₂ photocatalytic conversion to NO₃⁻.
• The Pd₂.₅Te phase demonstrates exceptional efficiency for solar-driven N₂ fixation without sacrificial agents.
• This work underscores the importance of phase control in designing advanced photocatalysts for sustainable chemical synthesis.