High photocatalytic performance of ferroelectric AgNbO3 in a doping state

The pure AgNbO3 photocatalyst with intrinsic electric field has aroused much interest due to its potential in promoting photocatalytic activity, but the performance was generally restricted by its relative fast recombination of photo-induced charges. Herein, Ag(1–3x)NdxNbO3 (x = 0, 0.01, 0.02, 0.03, 0.04, 0.05) powders with good crystalline structures were prepared by conventional solid-state reaction. The photocatalytic capacity of AgNbO3 powders was observably improved by Nd3+ doping due to the enhanced separation of photogenerated charges. In contrast to the pristine one, the photocatalytic efficiency of Ag(1–3x)NdxNbO3 with x = 0.02 (ANN002) raised to 2.78 times (98.6% within 30 min) and the corresponding reaction rate constant increased to 9.87 times (0.1905 min−1 within 15 min) under visible light. The built-in electric field arising from the ferroelectricity of ANN002 may effectively restrain the recombination of photogenerated electron–hole pairs. The superoxide radicals (·O2-), holes (h+) and hydroxyl radicals (·OH) are involved in the rhodamine B (RhB) degradation activity, and ·O2- and h+ play the major part. Besides, ANN002 achieved the complete RhB degradation under sunlight within 15 min and was able to degrade two other pollutants (methylene blue and tetracycline) under visible light within 30 min, indicating its potential application in photocatalytic field.