Efficient solar light photocatalytic degradation of commercial pharmaceutical drug and dye using rGO-PANI assisted c-ZnO heterojunction nanocomposites

The major requirement of a solar light-activated photocatalyst is the effective utilization of the light-induced electron-hole pair and exciton lifetime. Herein, the reduced graphene oxide and polyaniline assisted carbon doped porous ZnO (c-ZnO) heterojunction nanocomposites (RPZ nanocomposites) were designed for enhanced photocatalytic degradation of the commercially available pharmaceutical antibiotic drug amoxicillin and clavulanate potassium (ACP) and methylene blue (MB) dye using natural sunlight. The surface morphology, phase purity, and bonding environment of the prepared RPZ heterojunction nanocomposite were analyzed using scanning electron microscopy, X-ray diffraction, and soft X-ray absorption spectroscopy, respectively. In comparison with pure ZnO, a doping and composite formation reduced the bandgap energy from 3.34 to 2.80 eV, calculated using the Tauc plot. From photocatalytic degradation studies, the as-prepared RPZ heterojunction nanocomposite efficiently degraded 95% and 47% of MB dye and ACP in 100 min under natural sunlight with the reaction rates of 0.0296 and 0.0055 min-1, respectively. The removal efficiency of the photocatalyst was obtained to be 95% and 46.14% for MB dye and ACP, respectively.

Automated summary

This study designed a reduced graphene oxide and polyaniline assisted carbon-doped porous ZnO nanocomposite for enhanced photocatalytic degradation of dyes and pharmaceuticals. The reduced bandgap energy through doping and composite formation improved the degradation efficiency. Experimental results showed that the new nanocomposite exhibited high degradation efficiency for the dye and antibiotics.