Unraveling the enhanced photocatalytic decomposition efficacy of the Al-doped ZnO nanoparticles@graphene sheets

Abstract

This study reports thein situwet chemical synthesis of Al-doped ZnO nanoparticle hybridized graphene (ZnO_Al/G) nanocomposite for the photocatalytic decomposition of methylene blue dye. The graphene-amalgamated Al-doped ZnO sample evidences a more enhanced photocatalytic decomposition performance than the pristine and Al-doped ZnO nanoparticles. Powder x-ray diffraction study reveals the addition of Al and graphene with the ZnO does not alter the hexagonal wurtzite phase of ZnO. Surface morphological results of the ZnO_Al/G nanocomposite obtained from scanning electron microscopy and transmission electron microscopy show that the Al-doped ZnO nanoparticles are fastened firmly to the graphene sheets. The Al and graphene inclusion does not alter the absorption onset of the ZnO, except for an enhanced light absorption in the visible region. The ZnO_Al/G nanocomposite imparts a higher photocatalytic decomposition rate constant (k) of about 0.0214 m(-1), while the values of pristine and Al-doped ZnO nanoparticles are about 0.0143 and 0.0129 m(-1), respectively. A plausible decomposition mechanism for the augmented photocatalytic performance of the ZnO_Al/G nanocomposite has been discussed in detail.