Novel Fabrication and Enhanced Photocatalytic MB Degradation of Hierarchical Porous Monoliths of MoO3 Nanoplates

Yang Liu,Farid Akhtar,Peizhong Feng,Xinyang Jiao,Zhang Wang

doi:10.1038/s41598-017-02025-3

Yang Liu, Farid Akhtar + Show 3 more

Open Access

https://doi.org/10.1038/s41598-017-02025-3

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Abstract

Porous monoliths of MoO3 nanoplates were synthesized from ammonium molybdate (AHM) by freeze-casting and subsequent thermal treatment from 300 to 600 °C. Pure orthorhombic MoO3 phase was obtained at thermal treatment temperature of 400 °C and above. MoO3 monoliths thermally treated at 400 °C displayed bimodal pore structure, including large pore channels replicating the ice crystals and small pores from MoO3 sheets stacking. Transmission electron microscopy (TEM) images revealed that the average thicknesses of MoO3 sheet were 50 and 300 nm in porous monoliths thermally treated at 400 °C. The photocatalytic performance of MoO3 was evaluated through degradation of methylene blue (MB) under visible light radiation and MoO3 synthesized at 400 °C exhibited strong adsorption performance and best photocatalytic activity for photodegradation of MB of 99.7% under visible illumination for 60 min. MoO3 photocatalyst displayed promising cyclic performance, and the decolorization efficiency of MB solution was 98.1% after four cycles.

Highlights

The growth speed and orientation of the ice crystals can be controlled to obtain unidirectional porous scaffolds
The results showed that the as-synthesized MoO3 exhibited high-efficiency catalytic as well as adsorption performance, and the decomposition efficiency of 30 mg/L methylene blue (MB) was 98.8% under illumination for 30 min, which was far superior to the decomposition efficiencies reported in literature
Porous AHM thermally treated at 400 °C shows that all the diffraction peaks of the synthesized products correspond to only α-MoO3

Summary

OPEN Novel Fabrication and Enhanced

Photocatalytic MB Degradation of Hierarchical Porous Monoliths of Received: 19 December 2016 Accepted: 4 April 2017 Published: xx xx xxxx. Porous monoliths of MoO3 nanoplates were synthesized from ammonium molybdate (AHM) by freezecasting and subsequent thermal treatment from 300 to 600 °C. MoO3 monoliths thermally treated at 400 °C displayed bimodal pore structure, including large pore channels replicating the ice crystals and small pores from MoO3 sheets stacking. The photocatalytic performance of MoO3 was evaluated through degradation of methylene blue (MB) under visible light radiation and MoO3 synthesized at 400 °C exhibited strong adsorption performance and best photocatalytic activity for photodegradation of MB of 99.7% under visible illumination for 60 min. Hierarchically porous monoliths of α-MoO3 nanoplates of high purity were synthesized through the combination of the freeze-drying and thermal treatment, and the phase composition and microstructure were investigated. The results showed that the as-synthesized MoO3 exhibited high-efficiency catalytic as well as adsorption performance, and the decomposition efficiency of 30 mg/L MB was 98.8% under illumination for 30 min, which was far superior to the decomposition efficiencies reported in literature

Results and Discussion

Conclusions

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