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 TiO2/CaTi4O9/CaTiO3 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 TiO2/CaTi4O9/CaTiO3 composite can effectively promote the transfer of electrons (e-), thus reducing its recombination on TiO2/ CaTi4O9/CaTiO3, which provides much more electrons for H2 production and the Cr (VI) reduction reactions. A remarkable improvement in H2 production and Cr (VI) reduction were achieved over TiO2/CaTi4O9/CaTiO3 modified with RGO. Notably, with optimum RGO content, the 1.0 wt%RGO-TiO2/CaTi4O9/CaTiO3 showed the best H2 production performance of 34.78 mmol h- 1 g- 1, which is 15.09 and 6.86 times higher than TiO2 and CaTiO3, respectively. Moreover, an excellent Cr (VI) reduction rate of 53.79% was also achieved over 1.0 wt% RGO-TiO2/CaTi4O9/CaTiO3, which is 4.82 and 5.55 times higher than that of TiO2 and CaTiO3, respectively.