Photocatalytic Hydrogen Peroxide Production from Water Using a Cyano-Covalent Organic Framework

Abstract

The demand for sustainable chemical production methods has led to significant advancements in photocatalysis. This study explores the photocatalytic production of hydrogen peroxide (H2O2) from water using a covalent organic framework (CYANO–COF) synthesized from triformylphloroglucinol (Tp) and 4,4′-diamino-[1,1′-biphenyl]-3,3′-dicarbonitrile (Bp–CN) via Schiff-base condensation. The synthesized COF material exhibited a predominantly AB stacking structure with an optimal band gap (2.22 eV) for visible-light absorption and effective charge separation. Furthermore, the photoelectrochemical characterizations revealed the photoresponsive nature of the material by creating a high charge density under illumination. Under illumination, the photocatalyst demonstrated efficient H2O2 generation with production rates of 550 μmolg–1h–1 using only water and 371 μmolg–1h–1 in the presence of ethanol. The sacrificial-agent-free system aligns with green chemistry principles, simplifying reaction conditions and reducing the environmental impact. Mechanistic studies confirmed the role of photoinduced electron–hole pairs in water oxidation and oxygen reduction. This research underscores the potential of CYANO–COF materials in sustainable H2O2 production using only water and sunlight thus highlighting avenues for optimizing long-term stability and efficiency.