The distinct effect of RGO coupling on boosting hydrogen production and Cr(VI) reduction over the TiO2/CaTi4O9/CaTiO3 photocatalyst.

Here, a composite material comprised of inner ternary TiO 2 /CaTi 4 O 9 /CaTiO 3 nanoparticles and outer reduced graphene oxide (RGO) layer was fabricated and further applied as the photocatalyst for hydrogen production and Cr(VI) reduction. The PL result shows that the intimate interface between RGO and TiO 2 /CaTi 4 O 9 /CaTiO 3 composite can effectively promote the transfer of electrons (e - ), thus reducing its recombination on TiO 2 /CaTi 4 O 9 /CaTiO 3 , which provides much more electrons for H 2 production and the Cr (VI) reduction reactions. A remarkable improvement in H 2 production and Cr (VI) reduction were achieved over TiO 2 /CaTi 4 O 9 /CaTiO 3 modified with RGO. Notably, with optimum RGO content, the 1.0 wt%RGO-TiO 2 /CaTi 4 O 9 /CaTiO 3 showed the best H 2 production performance of 34.78 mmol h−1 g−1, which is 15.09 and 6.86 times higher than TiO 2 and CaTiO 3 , respectively. Moreover, an excellent Cr (VI) reduction rate of 53.79% was also achieved over 1.0 wt%RGO-TiO 2 /CaTi 4 O 9 /CaTiO 3 , which is 4.82 and 5.55 times higher than that of TiO 2 and CaTiO 3 , respectively. • Reduced graphene oxide (RGO) surface-modified TiO 2 /CaTi 4 O 9 /CaTiO 3 composite was synthesized. • The electron transfer to the reduced graphene oxide (RGO) and reduced charge recombination has been investigated. • RGO-TiO 2 /CaTi 4 O 9 /CaTiO 3 composite showed excellent photocatalytic performance in both H 2 production and Cr(VI) reduction. • A dual-Z-scheme was established in the ternary composite. [ABSTRACT FROM AUTHOR]