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

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 H-2 was better than that of pure TiO2. Under the irradiation of a 300 W Xe arc lamp, the H-2 production rate of the Cr2O3/C@TiO2 composite that was calcined at 500 degrees C was 446 mu mol h(-1) g(-1), which was approximately four times higher than that of pristine TiO2 nanoparticles. Moreover, the composite exhibited the high H-2 production rate of 25.5 mu mol h(-1) g(-1) under visible light irradiation (lambda > 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. (C) 2021, Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by Elsevier B.V. All rights reserved.