Preparation of a novel type-II FePc/PDINH heterojunction photocatalyst via electrostatic interactions for high-efficient phenol degradation

The photocatalytic removal of organic pollutants from wastewater has received attention due to its environmental friendliness and low cost in recent years. Herein, a type-II heterojunction iron(II) phthalocyanine/perylene-3,4,9, 10-tetracarboxylic diimide (FePc/PDINH) composite photocatalyst was fabricated via electrostatic interactions, and its photocatalytic degradation performance and mechanism were explored. The FePc/PDINH photocatalyst exhibited a photocatalytic phenol removal efficiency of 95.7 % within 30 min. The degradation rate was 13.6 and 248.8-times higher than that of single PDINH and FePc under the optimal reaction conditions. The photocurrent response and photoluminescence spectroscopy results indicated that electron-hole pair recombination was hindered, and the migration rate of photogenerated carriers was improved due to the formation of a type-II heterojunction. The quenching and electron paramagnetic resonance spectroscopy results showed that ·O2− and 1O2 were the main reactive oxygen species involved in phenol degradation. Some common coexisting anions significantly inhibited phenol degradation. The density functional theory (DFT) calculations confirmed that electrostatic interactions between FePc and PDINH enhanced the photocatalytic activity. This allowed remarkable electron transfer at the interface and facilitated efficient interfacial charge migration and separation. This study offers a fresh design strategy for PDINH-based photocatalytic composites for organic pollutant degradation.