Hydrogenated hematite nanoplates for enhanced photocatalytic and photo-Fenton oxidation of organic compounds

Hematite (alpha-Fe2O3) has been widely used as a photocatalyst for photo-Fenton oxidation due to its low cost, environmental friendliness, and high efficiency. The Photo-Fenton oxidation performance can be improved for practical applications via bandgap engineering of the photocatalyst. Herein, hematite nanoplate (HNP) is synthesized via a solvothermal method and a hydrogenation treatment, resulting in hydrogenated HNP (H-HNP). Materials characterizations demonstrate the even distribution of oxygen vacancies, formation of Fe (II) species on H-HNP, the enhanced light absorption, and separation of photogenerated e(-)/h(+) pairs. Under simulated solar light, in comparison with pristine HNP, the H-HNP delivered significantly higher photo-Fenton oxidation activities under near-neutral pH conditions for the degradation of 50 mg L-1 Rhodamine B, Congo red, and Methylene blue after 20 min, i.e., 92.7%, 98.2%, and 77.2%, respectively. Mechanistic explorations, including XPS and radical trapping analysis, suggest that positively charged holes (h(+)) and catalytically formed hydroxyl radicals ((OH)-O-center dot) were the main factors contributing to the higher photo-Fenton oxidation performance of H-HNP. Overall, hydrogenation treatment is an easy and effective means for bandgap engineering to improve the photocatalytic performance of photocatalysts as demonstrated by the as-prepared H-HNP as a high-performance photocatalyst for the photo-Fenton oxidation reaction.