Unsymmetric Protonation Driven Highly Efficient H2O2 Photosynthesis in Supramolecular Photocatalysts via One-Step Two-Electron Oxygen Reduction.

Abstract

Photocatalytic hydrogen peroxide (H2O2) production has emerged as an attractive alternative to the traditional anthraquinone process. However, its performance is often hindered by low selectivity and sluggish kinetics of oxygen reduction reaction (ORR). Herein, we report an anthrazoline-based supramolecular photocatalyst, SA-SADF-H+, featuring an unsymmetric protonation structure for H2O2 photosynthesis from water and air.The introduction of unsymmetric protonation disrupts the initial mirror symmetry of SADF, significantly enhancing the molecular dipole and facilitating efficient charge separation and electron transfer. Additionally, this modification increases the hydrophilicity of SA-SADF-H+, enabling the interaction of water and dissolved oxygen with the catalytic sites. The altered electron density distribution creates numerous dual active sites for Yeager-type O2 adsorption, facilitating an efficient ORR towards H2O2 via a direct one-step two-electron pathway. Notably, SA-SADF-H+ achieves an outstanding photocatalytic H2O2 production at a rate of 4667 μmol L-1 h-1, with a remarkable solar-to-chemical conversion (SCC) of 1.35%, surpassing most organic photocatalytic systems. Furthermore, SA-SADF-H+ demonstrates remarkable photocatalytic antibacterial activity, achieving 100% antibacterial efficiency against Staphylococcus aureus within 60 min.