Lattice Defects Engineering in W-, Zr-doped BiVO₄ by Flame Spray Pyrolysis: Enhancing Photocatalytic O₂ Evolution

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.