Electrochemical hydrogen storage in Pd-coated porous silicon/graphene oxide

Abstract

In this study, P-type single crystal silicon (Si) was used to make porous silicon (PS) using an anodization cell. The prepared PS samples were first coated with Pd nanoparticles by electroless method (Pd/PS); then, graphene oxide (GO) sol was spin coated on them. Pd/PS coated with GO (GO-Pd/PS/Si) characterization has been carried out using field emission scanning electron microscopy (FESEM), Raman spectroscopy and X-ray diffraction (XRD). Electrochemical characterization and hydrogen storage were studied for all electrodes (Si, PS, Pd/PS and GO-Pd/PS/Si) by cyclic voltammetry (CV), galvanostatic charge/discharge and electrochemical impedance spectroscopy (EIS), respectively. The highest hydrogen storage capacity was obtained for GO-Pd/PS/Si, which was 546.1 mAh g−1 equal to 2.1 wt% hydrogen. The results indicate that the storage capacity of the GO-Pd/PS/Si electrode decreases only 1% of initial capacitance, after 100 cycles. Also, the EIS studies show that GO-Pd/PS/Si electrode performs electrochemically better than other electrodes. Considerable hydrogen storage in GO-Pd/PS/Si shows that this newly synthesized material could be a good candidate to be used in mobile hydrogen storage applications.