scholarly journals Flame Spray Pyrolysis Engineering of Nanosized Mullite-Bi2Fe4O9 and Perovskite-BiFeO3 as Highly Efficient Photocatalysts for O2 Production from H2O Splitting

Energies ◽  
2021 ◽  
Vol 14 (17) ◽  
pp. 5235
Author(s):  
Pavlos Psathas ◽  
Maria Solakidou ◽  
Asterios Mantzanis ◽  
Yiannis Deligiannakis

Bi-Fe oxides are stable materials with potential photocatalytic activity under solar light photons. So far, however the photocatalytic potential of pure-phase nanosized mullite-Bi2Fe4O9 has not been studied. Usually, synthesis of pure-phase nanosized mullite-Bi2Fe4O9 is hampered by co-formation with perovskite BiFeO3. Herein we demonstrate that pure-phase mullite-Bi2Fe4O9 nanoparticles prepared by Flame Spray Pyrolysis (FSP) technology are highly efficient O2 production photocatalysts, achieving >1500 μmol g−1h−1. This outperforms all -so far reported- O2 production Bi-Fe-O photocatalysts. We present an FSP-based process for production of a versatile Bi-Fe-O platform, that can be easily optimized to obtain 100% mullite-Bi2Fe4O9 or 100% perovskite-BiFeO3 or their heterojunctions. The phase-evolution of the Bi-Fe-O materials has been studied by XPS, Raman, and EPR spectroscopies. Short post-FSP annealing process impacts the photoactivity of the BiFeO3 and Bi2Fe4O9 in distinct ways. Fe2+ centers in BiFeO3 can improve dramatically its O2 production efficiency, while solid-melt formation in Bi2Fe4O9 is a limiting factor.

Nanomaterials ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 501
Author(s):  
Panagiota Stathi ◽  
Maria Solakidou ◽  
Yiannis Deligiannakis

A flame spray pyrolysis (FSP) method has been developed, for controlled doping of BiVO4 nanoparticles with W and Zr in tandem with the oxygen vacancies (Vo) of the BiVO4 lattice. Based on XPS and Raman data, we show that the nanolattice of W-BiVO4 and Zr-BiO4 can be controlled to achieve optimal O2 evolution from H2O photocatalysis. A synergistic effect is found between the W- and Zr-doping level in correlation with the Vo-concentration. FSP- made W-BiVO4 show optimal photocatalytic O2-production from H2O, up to 1020 μmol/(g × h) for 5%W-BiVO4, while the best performing Zr-doped achieved 970 μmol/(g × h) for 5%Zr-BiVO4. Higher W-or Zr-doping resulted in deterioration in photocatalytic O2-production from H2O. Thus, engineering of FSP-made BiVO4 nanoparticles by precise control of the lattice and doping-level, allows significant enhancement of the photocatalytic O2-evolution efficiency. Technology-wise, the present work demonstrates that flame spray pyrolysis as an inherently scalable technology, allows precise control of the BiVO4 nanolattice, to achieve significant improvement of its photocatalytic efficiency.


2021 ◽  
pp. 111426
Author(s):  
Naphaphan Kunthakudee ◽  
Pongtanawat Khemthong ◽  
Chuleeporn Luadthong ◽  
Joongjai Panpranot ◽  
Okorn Mekasuwandumrong ◽  
...  

Langmuir ◽  
2021 ◽  
Author(s):  
Abhijit H. Phakatkar ◽  
Mahmoud Tamadoni Saray ◽  
Md Golam Rasul ◽  
Lioudmila V. Sorokina ◽  
Timothy G. Ritter ◽  
...  

Energies ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 817
Author(s):  
Maria Solakidou ◽  
Yiannis Georgiou ◽  
Yiannis Deligiannakis

Noble metal-TiO2 nanohybrids, NM0-TiO2, (NM0 = Pt0, Pd0, Au0, Ag0) have been engineered by One-Nozzle Flame Spray Pyrolysis (ON-FSP) and Double-Nozzle Flame Spray Pyrolysis (DN-FSP), by controlling the method of noble metal deposition to the TiO2 matrix. A comparative screening of the two FSP methods was realized, using the NM0-TiO2 photocatalysts for H2 production from H2O/methanol. The results show that the DN-FSP process allows engineering of more efficient NM0-TiO2 nanophotocatalysts. This is attributed to the better surface-dispersion and narrower size-distribution of the noble metal onto the TiO2 matrix. In addition, DN-FSP process promoted the formation of intraband states in NM0-TiO2, lowering the band-gap of the nanophotocatalysts. Thus, the present study demonstrates that DN-FSP process is a highly efficient technology for fine engineering of photocatalysts, which adds up to the inherent scalability of Flame Spray Pyrolysis towards industrial-scale production of nanophotocatalysts.


2003 ◽  
Vol 150 (2) ◽  
pp. H38 ◽  
Author(s):  
Y. C. Kang ◽  
J. R. Sohn ◽  
H. S. Yoon ◽  
K. Y. Jung ◽  
H. D. Park

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