Simultaneous realization of direct photodeposition and high H <sub>2</sub> ‐production activity of amorphous cobalt sulfide nanodot‐modified rGO/TiO <sub>2</sub> photocatalyst
Feng Chen, Hong-Fei Feng, Wei Luo, Ping Wang, Huogen Yu, Jiajie Fan
Abstract
Abstract To realize highly efficient hydrogen production of graphene‐based photocatalysts, it is greatly important to increase more interfacial active sites onto graphene. In this work, the highly efficient CoS x ‐rGO (reduced graphene oxide)/TiO 2 composite photocatalyst was synthesized via a simple two‐step method, including the hydrothermal loading of rGO nanosheets onto TiO 2 nanoparticles and the subsequent photodeposition process of CoS x nanodots (0.5–2 nm) on the rGO nanosheets. Photocatalytic experimental results confirmed that the CoS x ‐rGO/TiO 2 photocatalyst displayed a distinctly higher photocatalytic H 2 ‐evolution activity than the TiO 2 photocatalyst. The highest hydrogen‐production efficiency of obtained CoS x ‐rGO/TiO 2 (10%) achieved 256.97 μmol·h −1 , which was distinctly higher than that of TiO 2 (4.41 μmol·h −1 ), rGO/TiO 2 (20.19 μmol·h −1 ) and CoS x /TiO 2 (132.67 μmol·h −1 ). According to the results of various characterizations and tests, the synergistic‐effect mechanism of CoS x nanodots and rGO nanosheets is proposed to explain the increased photocatalytic performance of CoS x ‐rGO/TiO 2 photocatalytic material, namely the rGO nanosheets cause the quick transfer of photo‐induced carriers from TiO 2 to CoS x nanodots, and then CoS x nanodots work as hydrogen‐production active sites to quickly generate H 2 . The present study may offer innovative ideas for the preparation and application of new highly efficient and inexpensive photocatalytic materials.