Photocatalytic dye degradation by graphene oxide doped transition metal catalysts

This study involved the synthesis and characterization of novel graphene oxide (GO) nanostructured materials modified with transition metal elements (Fe, Co, Ni, and Cu) as co-catalyst by using the chemical precipitation method. Microscopy analysis showed the formation and distribution of metal nanoparticles on the GO matrix and the co-existence of doped elements was identified using energy dispersive X-ray (EDX) spectroscopic analysis. The characteristic vibration bands of GO were examined by using Raman analysis. Brunauer-Emmett-Teller (BET) measurements confirmed decrement in the surface area of GO after metal addition. The photoelectrochemical performance and methyl orange (MO) degradation performance was investigated under ultraviolet light irradiation. The photocurrent of GO was significantly improved after the addition of metal nanoparticles. Predominantly, the Co and Ni-modified GO samples showed a high photocurrent generation of 64.9 μA/cm2 and 54.4 μA/cm2 respectively. The photocatalytic studies revealed that the modified GO samples exhibited greater dye degradation efficiency than the pristine GO. Among modified GO samples, Co and Ni-modified GO exhibited a remarkable photodegradation efficiency (84%) and rate constants (k = 13 ×10−3 min−1 & 16 ×10−3 min−1). The results imply that the Co and Ni-modified GO samples are the most efficient photocatalysts for MO dye removal.