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

Abstract

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.