Construction of Heterojuncted Photocatalyst with TiO 2 Quantum Dots and Graphene Oxide Nanosheets for High-Efficient Photocatalysis

To overcome the recombination issue of photocarriers, TiO2 quantum dots (QDs, nanoparticles in a few nanometers) were used to form heterojunctions with graphene oxide nanosheets. This combination has significantly enhanced the photocatalytic activity by providing more active reaction sites at the nanoscale surface and suppressing photocarrier recombination through fast separating the photocarriers by the internal electric field in the TiO2/graphene oxide heterojunctions. The enhancement in photocatalytic activity has been evidenced by the improved hydrogen generation rate in photoelectrochemical water splitting, about 30% higher than that of bare TiO2 QDs in the same situation. Moreover, the TiO2/graphene oxide composite also exhibits a lower flat band potential, which means a higher reducing potential of photo-excited electrons.