Photocatalytic efficiency enhancement of plasma-sprayed TiO2 coatings under external bias voltage

TiO2 coatings were prepared on stainless steel by plasma spraying. The photocatalytic efficiencies of as-sprayed coatings were evaluated through the photo mineralization of methylene blue. External bias voltages applied to the coatings have shown an enhancement of the photocatalytic efficiency reducing the recombination of photogenerated electron–hole pairs. A more efficient photocatalytic reaction would take place when a higher external bias is imposed, because the force of recombination suppression is strengthened when the external bias is higher. The highest photocatalytic efficiency enhancement was about 46%.