Evaluation of practical application potential of a photocatalyst: Ultimate apparent photocatalytic activity

Suffered from rapid recombination of electrons and holes, apparent photocatalytic activity (APA) of all photocatalysts can never achieve their theoretical ultimate values. But the upper limit of practical APA is of great significance to evaluate the practical application potential of a photocatalyst. Thus, in this work, the concept of ultimate apparent photocatalytic activity (UAPA) was firstly proposed and a convenient evaluation method was first established based on the nature that EDTA-2Na can exclusively scavenge photo-excited holes, and methyl orange (MO) is mainly attacked by superoxide radical (center dot O2- ) which is produced instantly by photo-excited electrons. From a macro perspective, six popular photocatalysts were designedly selected to verify the feasibility and application scope of the proposed UAPA evaluation method. Moreover, center dot O2- production rate and photocurrent intensity were measured by spectroscopy and spectrum analyses, and theoretical carrier concentrations were calculated by density functional theory (DFT) to further confirm the rationality and reliability of the proposed method. Positive responses of all the tests guarantee that the proposed UAPA could precisely evaluate the application potential of a photocatalyst and rank the photocatalysts according to their practical potential.

Automated summary

The concept of Ultimate Apparent Photocatalytic Activity (UAPA) was proposed and an evaluation method was established based on the nature that EDTA-2Na can selectively scavenge photo-excited holes. Experimental data and analyses confirmed the feasibility and application scope of the method, further supported by spectroscopic measurements and theoretical calculations for carrier concentrations. This method allows for precise evaluation of the application potential and ranking of photocatalysts according to their practical potential.