Boosting the photocatalytic H2 evolution activity of Fe2O3 polymorphs (α-, γ- And β-Fe2O3) by fullerene [C60]-modification and dye-sensitization under visible light irradiation

Abstract

C60/Fe2O3 nanocomposites are successfully prepared, well characterized, and employed in visible-light-driven photocatalytic H2 production. The Fe2O3 polymorphs show obvious broad-spectrum absorption, even close to the near infrared region (780-900 nm). The H2 production rates of β-Fe2O3 and γ-Fe2O3 are almost 2.1 times and 3.1 times higher than α-Fe2O3 (which itself is close to that of g-C3N4). This demonstrates that carefully controlling the polymorphs can tune the photocatalysts' H2 production properties. After modifying the Fe2O3 polymorphs with C60, the sample with 0.5 wt% C60/β-Fe2O3 has the optimum photocatalytic activity. This result indicates that the strength of the interaction and interfacial contact between C60 and Fe2O3 polymorphs plays an important role in the enhancement of photocatalytic activity, which can improve the transmission efficiency of photogenerated electrons via a conjugated three-dimensional π system. Fluorescein is introduced as a photosensitizer and the optimum mass ratio of fluorescein + 0.5C60/β-Fe2O3 is 1:1, which significantly boosts the photocatalytic H2 evolution rate of 0.5C60/β-Fe2O3 from 321.8 to 1665.0 μmol g-1 h-1. Meanwhile, the composites exhibit high stability and reusability.