▎ 摘　　要

Single step hydrothermally synthesized the stable cerium oxide (CeO2) nanorods decorated on layered surface of graphene oxide (GO) flakes. The crystal surface structure of novel CeO2/GO nanocomposites were analysed by scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDX), X-ray diffraction (XRD), and Brunauer-Emmett-Teller (BET). Electrochemical behavior of the CeO2, GO and nanocomposites were explored from cyclic voltammetry (CV), galvanostatic charge/discharge (GCD), and electrochemical impedance spectroscopy (EIS) measurements using as active materials of the electrode. CeO2/GO nanocomposites displays higher specific capacitance (C-s, 616 Fg(-1)) than those of individuals at low scan rate of 2 mVs(-1) by CV studies. Nanocomposites has good stability by exhibiting 82 % of capacitive retention after 10 k cycles at 10 Ag-1. Symmetric device were fabricated using nanocomposite materials for both anode and cathode. The device produces a considerable C-s, specific energy (SE), specific power (SP) values such as 55.3 Fg-1, 23.1 Whkg(-1) and 5088 Wkg(-1) respectively. Using symmetric device, continued the cycle life studies at 10 Ag-1 for 5 k cycles, and exhibited a capacitance retention of 82 %. With a low overpotential of 112 mV, a small Tafel slope of 77.46 mV dec(-1), and long-term stability, the composites showed better HER performance.