Achieving photocatalytic water oxidation on LaNbON2 under visible light irradiation

摘要

cqvip:LaNbON_2 has narrow bandgap and wide visible-light absorption band, yet no photocatalytic water oxidation on LaNbON_2 has been reported. By a post-annealing treatment in Ar, anion vacancies were brought into LaNbON_2 as shown by EPR spectroscopy. These could act as donors in the semiconductor. And consequently the oxidative power of holes was enhanced as indicated by the difference between fermi level and valence band maximum(E_F-E_(VBM)) evaluated from valence band XPS. The annealed LaNbON_2 photocatalyst acquired water oxidation ability for the first time, which was improved by combining CoO_x as cocatalyst. Annealed LaNbON_2 derived from La_3NbO_7 had smaller particle size, higher concentration of anion vacancies, bigger E_F-E_(VBM) and better performance for photocatalytic oxygen evolution reaction than LaNbON_2 derived from LaNbO_4.