The Influence of the Ammonolysis Temperature on the Photocatalytic Activity of β-TaON

Abstract EN

Phase-pure tantalum oxynitride (β-TaON) powders were synthesized by thermal ammonolysis of Ta2O5 powders.

X-ray diffraction revealed an enlargement of the unit cell and an increase of the crystallite size with increasing ammonolysis temperature.

Scanning electron microscopy showed reduced particle sizes for β-TaON synthesized at 800 and 900∘C compared to the precursor oxide.

With increasing nitridation temperature the Brunauer-Emmett-Teller surface area was reduced and the nitrogen content increased.

UV-Vis spectroscopy showed a bandgap energy of 2.6–2.4 eV.

The highest oxygen evolution rate of 220 μmol·g−1·h−1 was achieved for β-TaON synthesized at 800∘C.

The factors determining the photocatalytic activity of β-TaON powders were found to be the specific surface area and defects in the β-TaON.