Nitrogen doped graphene quantum dots as a cocatalyst of SrTiO3(Al)/CoOx for photocatalytic overall water splitting

摘要

Aluminium doped strontium titanate, SrTiO3(Al), is considered as the most promising candidate photocatalyst for water splitting; however, it suffers from fast recombination of photogenerated charges and little photocatalytic activity for overall water splitting. Precious metals, such as RhCrOx, are always needed as cocatalysts to enhance the photocatalytic performance. Herein, nitrogen doped graphene quantum dots (NGQDs) were prepared and applied as a hydrogen evolution reaction (HER) cocatalyst of SrTiO3(Al)/CoOx for photocatalytic overall water splitting. The designed NGQDs/SrTiO3(Al)/CoOx is highly active for overall water splitting achieving a H-2 evolution rate of 18.8 mu mol h(-1) and an O-2 evolution rate of 9.0 mu mol h(-1), respectively. The NGQDs and CoOx are dispersed on the different crystal facets of octagonal SrTiO3(Al), which is beneficial to the spatial separation of photogenerated electrons and holes. The strong interaction between NGQDs and SrTiO3(Al) via Ti-O-C chemical bonds enhances the charge transfer and separation. Moreover, the pyrrole N species within NGQD networks act as active sites for the hydrogen evolution reaction.