Fast monitoring of organic dye degradation coupled with a colorimetric approach in a Ag-modified TiO2 nanotube photocatalytic system

Abstract

Monitoring the contents of organic dyes in real-time is crucial for the valuation of photocatalyst performance. To achieve this, a method of detecting organic dyes was designed based on color variations by using Ag nanoparticle modified TiO2 nanotubes (Ag/TiO2) as photocatalysts. The obtained Ag/TiO2 photocatalyst possesses strong visible-light absorption, and 1.0% Ag/TiO2 exhibited the best performance under UV and simulated sunlight. The investigation indicates that the photocatalytic activity of TiO2 nanotubes is greatly improved by the modification with silver. Moreover, the photodegradation intermediates and pathways are demonstrated by trapping experiments and density functional theory calculations. To quantitatively determine the concentration of methyl orange, a partial least squares model was built using RGB values and the concentration of a methyl orange solution. This finding provides a new idea to fabricate a sensor for point-of-care test of organic dyes in the field of environmental applications.