AgI loading BiOI composites with enhanced photodegradation efficiency for bisphenol A under simulated solar light

Area of Science:

• Materials Science
• Environmental Chemistry
• Photocatalysis

Background:

• Bismuth oxyiodide (BiOI) is a narrow band gap semiconductor activated by visible light.
• Efficient separation of photo-generated carriers and visible light utilization are crucial for photocatalysis.
• Bisphenol A (BPA) is a common environmental pollutant requiring effective degradation methods.

Purpose of the Study:

• To synthesize a novel AgI-BiOI 3D hierarchical composite for enhanced photocatalytic activity.
• To investigate the photocatalytic degradation of BPA using the synthesized AgI-BiOI composite under visible light.
• To evaluate the catalyst's durability, ecotoxicity, and degradation mechanism.

Main Methods:

• A facile solvothermal approach was employed to synthesize the AgI-BiOI composite.
• Photocatalytic degradation of BPA was conducted under simulated solar light.
• Free radical quenching experiments were performed to identify active species, and ecotoxicity was assessed using C. elegans.

Main Results:

• The AgI-BiOI composite (Ag:Bi molar ratio 1:8) exhibited significantly enhanced BPA degradation, with rate constants 3.7 and 14.5 times higher than pristine BiOI and AgI, respectively.
• The enhanced performance is attributed to improved light absorption and accelerated charge carrier separation due to the AgI-BiOI heterojunction.
• Positive holes (h+) and superoxide radicals (O2•−) were identified as the primary active species in BPA degradation.

Conclusions:

• The AgI-BiOI(1-8) composite demonstrates superior photocatalytic activity for BPA degradation under visible light.
• The catalyst exhibits low ecotoxicity towards C. elegans and its degradation intermediates show reduced toxicity over time.
• AgI-BiOI(1-8) is a promising, durable, and environmentally friendly candidate for solar light-driven photocatalytic applications.