Hello, You can change the initial pH for dye solution to reach for ZPC of catalyst....

By the way this dye needed to high time to decolorize that beyond to the amount of energy which it needed (wavelength of lamp) that affects on the band gap of catalyst, also it needed to adsorption time about 30 min before illumination by lamp...

I suggested to using a solar light after adsorption to 30 min....

Dear Luma,

thanks for your suggestion. Adsorption in a dark place for 30 minutes was performed before illumination. So this should not be the problem. However, I did not check pH of the solution. Can you please advice which acid/base or buffer is suitable for pH adjustment in this case?

Thanks.

Dear Mr. Michal,

You can use 0.1 M HCl and 0.1 M NaOH to control pH directly. Note don't used buffer because, buffer have salt and his acid or salt and his base... these compounds may be adsorption on catalyst surface and comparative the adsorption of dye on surface then, may be leaded to decrease the efficiency of decolorization of dye.

Please, note if the color of dye changes during changed the pH... you ignorant to it other pH, because the structure and the wavelength of dye will change.

Regards,

Boa tarde!

Tenho produzido amostras similares a sua e para a fotocatálise, meus resultados também são ruins. Penso que o problema deve estar na estreita faixa de bang gap da fase obtida (ErFeO3). Isto causa uma rápida ativação e desativação do catalisador - recombinação elétron/lacuna.

Abs., Vivian.