Synthesis of core-shell nanostructured Cr2O3/C@TiO2 for photocatalytic hydrogen production

Abstract

In this study, the Cr2O3/C@TiO2 composite was synthesized via the calcination of yolk–shell MIL-101@TiO2. The composite presented core–shell structure, where Cr-doped TiO2 and Cr2O3/C were the shell and core, respectively. The introduction of Cr3+ and Cr2O3/C, which were derived from the calcination of MIL-101, in the composite enhanced its visible light absorbing ability and lowered the recombination rate of the photogenerated electrons and holes. The large surface area of the Cr2O3/C@TiO2 composite provided numerous active sites for the photoreduction reaction. Consequently, the photocatalytic performance of the composite for the production of H2 was better than that of pure TiO2. Under the irradiation of a 300 W Xe arc lamp, the H2 production rate of the Cr2O3/C@TiO2 composite that was calcined at 500 °C was 446 μmol h−1 g−1, which was approximately four times higher than that of pristine TiO2 nanoparticles. Moreover, the composite exhibited the high H2 production rate of 25.5 μmol h−1 g−1 under visible light irradiation (λ > 420 nm). The high photocatalytic performance of Cr2O3/C@TiO2 could be attributed to its wide visible light photoresponse range and efficient separation of photogenerated electrons and holes. This paper offers some insights into the design of a novel efficient photocatalyst for water-splitting applications.