Unlocking One-Step Two-Electron Oxygen Reduction via Metalloid Boron-Modified Zn₃In₂S₆ for Efficient H₂O₂...

Area of Science:

• Materials Science
• Photocatalysis
• Green Chemistry

Background:

• The indirect two-step two-electron oxygen reduction reaction (2e⁻ ORR) is dominant for photocatalytic H₂O₂ synthesis.
• This process faces challenges including slow kinetics, catalyst degradation, and carrier-intermediate mismatch.

Purpose of the Study:

• To develop a novel photocatalyst for efficient direct one-step 2e⁻ ORR.
• To enhance hydrogen peroxide (H₂O₂) production rates and stability.

Main Methods:

• Engineered Zn₃In₂S₆ (ZnInS) with boron doping to create In-B dual-active sites.
• Utilized a metal-metalloid dual-site strategy to facilitate moderate O₂ adsorption and dual-channel electron transfer.
• Investigated the effect of lattice polarization and built-in electric fields induced by boron doping.

Main Results:

• Achieved a direct one-step 2e⁻ ORR pathway, bypassing sluggish indirect routes.
• Demonstrated a H₂O₂ production rate of 3121 µmol g⁻¹ h⁻¹, an 11-fold enhancement over pristine ZnInS.
• Obtained an apparent quantum yield of 49.8% at 365 nm and continuous production of medical-grade H₂O₂.

Conclusions:

• The metal-metalloid dual-site strategy and boron engineering effectively promote direct 2e⁻ ORR for superior H₂O₂ photosynthesis.
• The B-ZnInS photocatalyst offers a promising platform for efficient and stable H₂O₂ production.
• This work provides valuable insights for designing advanced photocatalysts for H₂O₂ synthesis and other applications.