Abstract
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.
Highlights
IntroductionSince the 1972 report by Fukushima and Honda [1] on the photocatalytic water splitting using TiO2 , several other types of semiconductors have been evaluated as photocatalysts
Using X-ray photoelectron spectroscopy (XPS) and Raman spectroscopies we have studied the interrelation between W- or Zr-doping and O-vacancies, in conjunction with photocatalytic O2 evolution
Pristine BiVO4 is included for comparison
Summary
Since the 1972 report by Fukushima and Honda [1] on the photocatalytic water splitting using TiO2 , several other types of semiconductors have been evaluated as photocatalysts. Tungtates [2], vanadates molybdates and niobates [3] have been found to be efficient photocatalysts for O2 evolution from H2 O. Among the most efficient O2 -evolving photocatalysts IrO2 stands-out as the best [3] its high-cost is prohibitive. O2 -produciton efficiencies for IrO2 photocatalysts are reported to be in the range. 5000–7000 μmol/(g × h) [3]. TiO2 as a reference material has been extensively studied for
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