Boron-treated hematite photoanode for enhanced photocatalytics activities

Abstract

As the demand of energy increases over the years, solar energy has emerged to be an uprising energy resource for its advantages such as abundance, renewable and environmentally friendly. Photocatalytic water splitting is the method in which solar fuel is obtained.

This report includes the studies of boron-treated hematite synthesized by spray pyrolysis and also the discovery of new surface treatment materials on boron-treated hematite to improve the overall photocatalytic performance of a photoanode.

With 15% boron treatment in hematite followed by a high temperature annealing process, a high photocurrent density of 0.83 mA/cm2 was obtained. It was believed that boron treatment increased the porosity in the hematite films and allowed more light trapping sites for absorption, thus improving the photoelectrochemical performance. Surface treatment carried out by ZnAc further increased the photocurrent density to 1.08 mA/cm2 due to formation of ZnO overlayers which acted as electron blocking layers and helped to reduce recombination. However, ZnO was found to be unstable at long illumination time and hence not a suitable option for surface treatment process.

On the contrary, TiO2 overlayers were found to deliver improvement in photocatalytic activity and proved to be a potential surface treatment material to improve the overall photoelectrochemical performance of the device.