Interference effects in H₂O₂ quantification: A comparative study of three common methods in photocatalytic systems

Area of Science:

• Photocatalysis research
• Chemical analysis techniques
• Materials science

Background:

• Accurate quantification of hydrogen peroxide (H2O2) is essential for evaluating photocatalyst performance.
• Commonly used methods like N,N-diethyl-1,4-phenylenediamine (DPD), iodometry, and cerium sulfate titration lack systematic reliability assessments.

Purpose of the Study:

• To comparatively analyze the effectiveness and reliability of DPD, iodometry, and cerium sulfate titration methods for H2O2 measurement in photocatalytic processes.
• To identify interferents affecting H2O2 quantification and assess the robustness of each analytical method.

Main Methods:

• Utilized model photocatalysts: graphitic carbon nitride (g-C3N4), titanium dioxide (TiO2), zinc selenide (ZnSe), and resorcinol formaldehyde (RF).
• Conducted a comparative analysis of DPD, iodometry, and cerium sulfate titration methods.
• Investigated the impact of reaction byproducts and nitrogen species (e.g., nitrite) as interferents.

Main Results:

• Byproducts formed during H2O2 generation interfere with accurate measurement.
• Cerium sulfate titration overestimates H2O2 production in photocatalysis, despite accuracy with standard solutions.
• Nitrite (NO2-) significantly interferes with iodometry, causing time-dependent overestimation.
• The DPD method exhibits strong resistance to interference from byproducts.

Conclusions:

• Standard H2O2 quantification methods are unreliable for photocatalytic applications due to interferents.
• Nitrogen species, especially nitrite, are critical interferents impacting iodometry and cerium sulfate titration.
• The DPD method is the most reliable technique for measuring H2O2 production in photocatalysis.