▎ 摘　　要

For the first time, a hybrid carbon material consisting of micron-sized carbon spheres and graphene (denoted as MS-GR) was prepared via a hydrothermal method. In this work, micron-sized carbon spheres were prepared using glucose and 1-butyl-3-methylimidazolium tetrafluoroborate as the starting materials through a hydro thermal method, and graphene was employed as purchased. One-pot and two-step hydrothermal methods were respectively employed to prepare MS-GR, and in each preparation method, three different amounts of graphene were added in the preparation system while maintaining the added amounts of other reagents identical for each prepared catalyst. As a result, six kinds of hybrid carbon materials were fabricated in this work. Next, MS-GR supported palladium composite catalysts were fabricated through a hydrothermal method using PdO center dot H2O as the palladium source. Metallic Pd particles, metallic Pd particles along with PdO were indicated by XRD patterns to be the main substances of the one-pot and two-step hydrothermally prepared MS-GR supported catalysts, respectively. As presented by the SEM images, micron-sized carbon spheres and individual graphene sheets as well as the small particles were exhibited clearly in all prepared catalysts, suggesting that all the resultant catalysts were a composite material. Most importantly, as indicated by the CV and CA curves, all synthesized catalysts showed obvious electrocatalytic activities for EOR. In particular, the peak current density of peak f for EOR in the CV curves on catalyst t-4 was as high as 29.1 mA cm-2, significantly larger than the previously reported values. And the current density of EOR measured by CA test on catalyst t-4 was retained as high as 2.83 mA cm-2 after 600 s, showing an excellent electrocatalytic durability. In this work, a carbon material constructed by micron-sized carbon spheres and graphene as well as a novel MS-GR supported Pd catalyst was developed for the first time, which was very helpful to the final commercialization of a Pd-based EOR electrocatalyst due to the greatly reduced the preparation cost and the facile preparation procedure.