Designing Optimal Metal-Doped Photocatalysts: Correlation between Photocatalytic Activity, Doping Ratio, and Particle Size

Semiconductor photocatalysis is an important process for a variety of applications. However, the high recombination rate is still a limiting factor for the photocatalytic activity of the current photocatalysts. Several strategies were employed in an attempt to reduce the recombination rate, including doping with transition metals. While there was some success in increasing the photocatalytic activity, the large discrepancy in the obtained results and the lack of an appropriate model to describe this mechanism are still unsolved problems. In this work, a theoretical model that describes the correlation between photocatalytic activity, doping ratio, and particle size is developed. As a basis for this model, a collection of optimal doping data for different particle sizes of doped titanium dioxide and zinc oxide was used. With this newly developed model it is now possible to predict the optimal dopant concentration for a photocatalyst of a given size.