Multifunctional photocatalyst of graphitic carbon embedded with Fe 2 O 3 /Fe 3 O 4 nanocrystals derived from lichen for efficient photodegradation of tetracycline and methyl blue.
Fufeng YanLijun HuMinghua WangShunjiang HuangShuai ZhangLinghao HeZhihong ZhangPublished in: Environmental technology (2023)
We propose a feasible and economical method of constructing biomass-based multifunctional photocatalysts with excellent adsorption performance and high photodegradation abilities toward tetracycline (TC) and methyl blue (MB) under visible light. A series of novel hybrids of porous graphitic carbon embedded with Fe 2 O 3 /Fe 3 O 4 nanocrystals (denoted as Fe 2 O 3 /Fe 3 O 4 @C) were derived from lichen doped with different dosages of Fe 3+ by calcination at 700°C under a N 2 atmosphere. The Fe 2 O 3 /Fe 3 O 4 @C hybrids exhibited nanoflake-like shapes, mesoporous structures, and efficient visible light harvesting, thus indicating enhanced adsorption ability and photoactivity toward pollutants. The formed Fe 2 O 3 /Fe 3 O 4 heterojunction improved the separation efficiency and inhibited the recombination of photogenerated carriers, whereas the carbon network improved the transfer of photogenerated electrons. Under optimised conditions, the Fe 2 O 3 /Fe 3 O 4 @C-1 hybrid demonstrated enhanced photodegradation efficiencies of 96.4% for TC and 100% for MB under visible light. In addition, electron spin resonance and trapping measurements were performed to identify active species and determine the photocatalytic mechanism toward pollutants. •O 2 - and •OH were the active species involved, playing critical roles in the TC and MB photodegradation processes. In addition, a bacterium test revealed that the products of TC degradation by Fe 2 O 3 /Fe 3 O 4 @C-1 showed low biological toxicity. This work provides a promising preparation strategy or biomass-based photocatalysts for application in environmental pollutant treatment.
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