Abstract
Graphite/rolled graphene oxide/carbon nanotubes (G/R-GO/CNTs) was prepared and applied as a photoanode for water splitting from exhaust car solution. R-GO was prepared from graphene oxide (GO) using the modified Hummer method after settle down in solution for 2 months to roll out. The R-GO coated the graphite (G) electrode using the dip-coating method to form G/R-GO. Finally, CNTs were prepared on the G/R-GO electrode by using the chemical vapor deposition method to form G/R-GO/CNT electrode. The images of field emission scanning electron microscope show the formation of relatively homogenous and uniform R-GO with an average diameter of about 140 nm. Also, the high density of CNTs was observed with uniform diameters distribution and lengths of CNTs up to several micrometers. The values of the current density of G/R-GO/CNT electrode for water splitting are changed from 0.82 mA cm(-2) in dark to 1.50 mA cm(-2) in light. The value of incident photon-to-current efficiency was 8.4% at 470 nm. The thermodynamic parameters were calculated, in which the activation energy (E-a), enthalpy (Delta H*), and entropy (Delta S*) values were 8.1 kJ mol(-1), 29.9 J mol(-1), and 56.4 J K-1 mol(-1), respectively.